204496883-Manual-Chemistry-2014

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MAJLI S PEPERI KSAAN MALAYSI A

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(MALAYSI AN EXAMI NATI ONS COUNCI L)

PEPERI KSAAN SI JI L TI NGGI PERSEKOLAHAN M ALAYSI A (MALAYSIA HIGHER SCHOOL CERTIFICATE EXAMINATION)

M anual for School-Based Assessment: Chemistry Practical Paper 4 962/4 STPM 2014

REM I NDER:

This manual is specifically for the use of teachers or examiners only and should not be given to unauthorised persons. __________________________________________________________________________________ This SBA M anual consists of 83 printed pages. Majlis Peperiksaan Malaysia 2013 RESTRI CTED

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Contents Page Part 1: 7HDFKHU¶V0DQXDOof Chemistry Practical Introduction

1

1.2

General Information

1

1.3

Recording of Assessment Marks

2

1.4

Moderation

3

1.5

Practical Work Assessment Guide

4

1.6

Project Assessment Guide

9

1.7

Summary of the Allocation of Mark for Each Experiment

16

1.8

Table of Summary of Experiment and Project

17

1.9

Preparation of Solutions

19

1.10

Guidelines for Experiments

22

1.11

List of Apparatus and Materials

36

Appendix A

49

Appendix B

50

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1.1

Part 2: 6WXGHQW¶V0DQXDOof Chemistry Practical 2.1

Introduction

51

2.2

Assessment of Practical Work and Project

51

2.3

Table of Summary of Experiment and Project

54

2.4

Experiment for First Term

56

2.5

Experiment for Second Term

66

2.6

Experiment for Third Term

75

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Part 1: Teacher's M anual of Chemistry Practical 1.1 I ntroduction This manual contains administration and guidelines on the implementation and assessment of the practical work and project which have to be carried out by the school.

1.1.2

Some of the skills that should be developed in STPM Chemistry subject (e.g. handling of apparatus, observation, interpretation of results, and planning) can only be fully acquired through practical work and project.

1.1.3

Continuous assessment of practical work and project in school throughout form six will ensure that direct assessment of all the desired practical and scientific skills of students can be made.

1.1.4

The practical science assessment is carried out in schools with the following objectives:

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1.1.1

(a)

To establish a practical work assessment system which is fair, accurate and comprehensive;

(b)

To improve the practical skills and the quality of practical work of students;

(c)

To inculcate independence, teamwork spirit, scientific attitudes and critical thinking among students.

1.2 General I nformation 1.2.1

The teacher in charge of the school-based assessment of practical chemistry will be provided with a softcopy of the 7HDFKHU¶V 0DQXDO ZKLFK FRQWDLQV WKH GHWDLOV RI the administration of practical chemistry assessment, practical work assessment guide and description of experiments.

1.2.2

Malaysian Examinations Council (MEC) will provide a softcopy of Teacher's and 6WXGHQW¶V 0DQXDO which can be downloaded from MEC Portal (http://www.mpm.edu.my) during the first term of form six. MEC will send username and password to Principal of the school for the downloaded purposes. The school is expected to make the duplicate copies of the Student's Manual which contain experiments to be given to each student.

1.2.3

MEC has determined 13 compulsory experiments and one project to be carried out by students which will be assessed by the teacher in three respective terms.

1.2.4

Experiments and project are to be carried out either individually or in groups as recommended in the Table of Summary of Experiments and Project on pages 17.

1.2.5

The teacher is expected to prepare the experiments according to this manual. MEC should be informed of any modifications made by using the Experiment Report Form (See Appendix B on page 51)

1.2.6

The recommended time to complete the practical works report and project report is as recommended in the Table of Summary of Experiments and Project on pages 17.

1.2.7

The information on each experiment should be given to the students before the experiment is carried out so that they can plan their practical work. 1

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1.2.8

The teacher should ensure that a student has been given a chance to acquire a particular skill before the assessment of that skill is made. For this purpose, the teacher should carry out similar experiments before carrying out the compulsory experiments.

1.2.9

The assessment of experimental skills should be done while the student is carrying out the experiment and also on the student¶VSUDFWLFDOZRUNUHSRUWThe assessment for the project should be done according to the project report and the oral presentation made by students.

1.2.10 For a student who is absent for an experiment with reason, the teacher can fix another date for the students to carry out the experiment.

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1.2.11 Students may write their practical work and project reports in either English or Bahasa Melayu. The practical work reports is to be submitted to the teacher on the same day the experiment is carried out unless otherwise stated. (Refer to the Table of Summary of Experiments and project on pages 17) Practical work reports which are not submitted RQWKHGD\RIWKHH[SHULPHQWDUHWREHDZDUGHGµ¶PDUN

1.2.12 Practical work reports which can be completed at home are to be submitted to the teacher not later than 3 days from the date of the experiment. A penalty of 2 marks is to be imposed for the reports submitted late to the teacher. Practical work reports which are submitted later than 7 days from the date RIWKHH[SHULPHQWDUHWREHDZDUGHGµ¶ mark. 1.2.13 The teacher is required to set the dateline for the submission of project in the specified date at the end of third term. A penalty of 2 marks is to be imposed for the reports submitted late to the teacher.

1.2.14 The oral presentation for the project work should be carried out by the teachers after the assessment of the project report of all students. If the teacher suggests that changes are required towards the project report after the oral presentation, the student needs to correct the project report.

1.2.15 For a student who has transferred to another school, the previous school is to send the student¶VUHSRUWVDQGWKH6WXGHQW5HFRUG Form which is partially completed and signed by the subject teacher, to the student¶VQHZVFKRRO

1.2.16 All practical work and project reports, and Student's Record Form are evidence; and should be kept by the school and destroyed under secure condition 6 months after the release of the STPM result in the following year.

1.3 Recording of Assessment M arks 1.3.1

Recording of the practical assessment marks of each student is to be done by the subject teacher on Student's Record Form (See Appendix A on page 50).

1.3.2

For each student, the teacher is to record the date of the experiment, the experiment number and mark given to each of the skills for the 13 compulsory experiments in the Student's Record Form. Marks are to be awarded in accordance with the practical work assessment guide on pages 4. The teacher will also record the date of oral presentation and mark given to each skill and component for the project in the Student's Record Form. Marks are to be awarded in accordance with the project assessment guide on pages 9. 2

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Remarks on the following FDVHV VKRXOG EH ZULWWHQ LQ WKH µNotes¶ FROXPQ RQ WKH Student's Record Form of the student involved. (a)

An experiment carried out at a later date for a student who was absent for the experiment.

(b)

Any penalty imposed due to late submission of practical and project reports to the teacher.

(c)

A student who has not finished all the experiments allocated (reasons to be stated).

(d)

A student who failed to submit all the practical and project reports (reasons to be stated).

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1.3.3

STPM 2014

1.3.4

Practical work and project assessment for the three terms should be completed four weeks before the written examination for third term

1.3.5

Once the practical and project assessment for every term is completed, the marks for the 13 compulsory experiments and one project is to be calculated and written in the µ2YHUDOO7RWDOPDUN¶FROXPQRQWKH6WXGHQW V5HFRUG Form. The full total mark for this practical work and project assessment is 225.

1.3.6

The total mark for each student must be submitted to MEC via electronic submission in the specified date.

1.3.7

The teacher carrying out the practical and project assessment are required to make a declaration that the entries of marks and the overall total mark in the Student's Record are correct by signing in the spaces provided.

1.4 M oderation 1.4.1

A common assessment standard for marking must be agreed upon if more than one teacher in the same school is involved in assessing the student's practical work and project to ensure that the internal assessment is carried out fairly and effectively.

1.4.2

All component of assessment are subjected to moderation by the moderator appointed by MEC.

3

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1.5 Practical Work Assessment Guide 1.5.1 The practical work should be graded based on the assessment criteria below. Skill

Description

M ark Range

The assessment is made through unobtrusive observations of any two experiments for every term which involved the use of different apparatus. Students should not be aware of the assessment.

The student exhibits correct techniques in handling apparatus and materials. The experiment is conducted without guidance.

6

The student is sufficiently capable of using and handling apparatus with minimum guidance.

4

The student can carry out simple practical work using common apparatus and materials provided with guidance.

2

M ax M ark

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A: Ability to use correct techniques and handling of apparatus and materials.

Criterion

B: Observations, measurements and recording

The assessment is based on the practical reports for five experiments (first term and second term) while three experiments (third term); which require students to make, record and report observations or results. Teachers are required to carry out the same experiments for moderation purposes.

6

For Volumetric Analysis (a) Correct readings (CR) and sufficient readings (SR)

Correct readings both the initial and final readings are recorded in the correct spaces and to two decimal places, except for zero. Sufficient readings at least two volume readings within the range of 0.10 cm3

1

1

5

(b) Correct average set (AS) and mean (M)

4

Correct average set correct difference between the final and initial readings.

1

Correct mean arithmetic mean for titres used/obtained to two decimals places.

1

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STPM 2014 Criterion

Description (c) Accuracy (The difference in mean value between the teacher and the student)

M ark Range

M ax M ark

1

If the difference is between 0.00 cm3 and 0.30 cm3

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For Physical Quantity and Technique (a) The table is complete and the data are filled in the correct spaces.

2

(Minus ONE mark if the table is not complete)

(b) All calculations of the data in the table are correct.

1

(c) Appropriate decimal places. Example:

Temperature readings up to one decimal place. (± 0.1 °C) Weight measurements up to two decimal places (± 0.01 g)

1

Burette readings up to two decimal places (± 0.05 cm3)

(d) Accuracy (The difference in mean value between the teacher and the student)

1

If the difference between 0% to 10%

5

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STPM 2014 Criterion

Description For Technique (Qualitative Analysis) (a) Filling the ³REVHUYDWLRQ´ column correctly (Minus ONE mark if the table is not complete)

The assessment is based on the practical reports for four experiments in first term, four experiments in second term, and three experiments in third term whereby students are required to answer the stipulated questions, interpret data and draw deductions.

For Volumetric Analysis, and Physical Quantities and Technique (Synthesis) (a) Each question, other than graphs which is correctly answered. (Minus ONE mark for the incorrect answer)

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5

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C: Interpretation of experimental observations and data

M ark Range

(b) Experiment which involve graphs.

Axes labelled and correct units (c) Correct shape of the graph

For Technique (Qualitative Analysis) (a) Filling the ³GHGXFWLRQ´FROXPQ correctly. (Minus ONE mark for each incorrect deduction) (b) Deducing the identity of the salt/ion correctly

6

Max 4

1

6

1

5

1

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Criterion

Description

The assessment is based on the practical report for two experiments whereby the students are required to plan the experiment by themselves. Read the tabulation on page 16.

M ark Range

The practical report for first term should have the following format: (a) Title

1

(b) Purpose

1

(c) Materials and apparatus (d) Theory/Introduction

1

(e) Procedure

1

(f)

2

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1

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D: Design and Planning of Investigation

STPM 2014

Results (Including calculations)/ observation

(g) Conclusion

1

(h) Comments (on the experiments and/or results and/or safety measures/ precautions)

1

9

The practical report for second term and third term (except project report) should have the following format: (a) Title

(b) Purpose (c) Materials and apparatus

(d) Theory/Introduction (e) Procedure/Tests (f)

7

4

Observations

(g) Deduction

4

(h) Conclusion/Identity of substance

1

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Criterion

Description

Assessment is conducted throughout the terms in first term and second term by observations. The students are expected to exhibit the scientific ethics and values such as:

M ark Range

(a) Excellent

5

(b) Good (c) Moderate

4 3

(d) Fair

2

(e) Poor

1

M ax M ark

5

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E: Scientific ethics and values

STPM 2014

self-reliance, trustworthiness, fairness, curiosity, inquisitiveness, initiative, innovative, receptive to new ideas, cooperative and caring for the environment.

8

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1.6 Project Assessment Guide The school will be notified of the theme of the project for the current year by MEC. The students are free to propose the title of the project based on the theme given.

1.6.2

The groups are expected to complete the task at the end of third term of form six where they will define the project focus, analyse and evaluate the information gathered, prepare an oral presentation and submit a written report.

1.6.3

The students will be assessed on their performances both as members of the group and as individuals.

1.6.4

The performance of individual students and that of groups is assessed through the following means: written report, overall quality of project report and oral presentation.

1.6.5

The report on project which has been done on third term should have the following format: (a) Title (b) Abstract (c) Introduction (d) Methodology (e) Observations, result and discussion (f) Conclusion (g) References/Bibliography

1.6.6

The assessment framework of the project work is shown in the table below.

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1.6.1

Component

Project report Project file

Oral Presentation

Group

Individual

Total

66.67 %

±

66.67%

±

10%

10%

13.33%

10%

23.33%

Total

100%

1.6.7

The project report should be at least 800 words and not more than 1500 words. The project report will be DVVHVVHGDVDJURXS¶VDVVHVVPHQWDQGVKRXOGEHDVVHVVHGEDVHGRQ the assessment criteria.

1.6.8

The oral presentation will be assessed individually and as a group. On the individual level, each student is given a minimum of 5 minutes per student. For groups of three students, a maximum time limit of 20 minutes is allocated; whereas for groups of two students, the maximum limit is 15 minutes. The group presentation also includes those that do not exceed 5 minutes. Each presentation will have a Q & A session.

1.6.9

Students need to be aware that the written work they submit must be entirely their own and cite any source that had been referred to. Teachers should try to encourage students to take responsibility for their learning, so that they accept ownership of the work and take pride in it.

9

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1.6.10 The project report should be assessed based on the assessment criteria below. Skill

Description

M ark Range

M ax M ark

Title

Clearly stated and related to the theme.

1

1

Abstract

Clearly stated about the summary of the project.

1

1

Introduction includes: Theory and Literature review

Presents some background information

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B: Observations, measurements and recording

Criterion

with reference quoted

2

without reference quoted but have some information background

1

weak background of research

0

4

Problem statements

Presents relevant problem statements

0

1

Objective

Presents relevant objectives of research

0

1

3

4

Methodology

Data collection procedures and techniques planned and outlined clearly. Presents easy-tofollow steps which are logical, adequately detailed, and repeatable.

Most of the data collection procedures and techniques are understandable but some lack detail or are confusing.

10

4

1

2

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STPM 2014 Criterion

Description

C: Interpretation of experimental observations and data

Observation, result and discussion

Observation: Data is well organised in a data table or paragraph well written in complete sentences. Result: All calculations were completed, and a correct graph is drawn. Discussion: Presents a logical and well structured explanation for findings.

M ark Range

5

M ax M ark

6

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Skill

11

Observation: Data is organised in a data table or paragraph written in complete sentences. Result: All calculations were completed, but not correctly or a graph is drawn, but it is not the correct. Discussion: Presents a logical explanation for findings.

3

4

Observation: Data is not organised in a data table or paragraph not written in complete sentences. Result: All calculations were not completed and a graph was not complete. Discussion: Presents an illogical explanation for findings.

1

2

6

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Description

M ark Range

M ax M ark

Suggests specific changes that would improve the investigation. Recommends relevant action or research in the future findings.

1

1

References/ Bibliography

Correct writing of references and cited appropriately.

1

1

Presentation of the project report

Presentation of the project is excellent (well structured, clear, concise and precise).

Criterion Conclusion

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D: Design and Planning of Investigation

STPM 2014

Project file evidence

12

2

2

Presentation of the projects is adequate.

1

Evidences including log book are neat, accurate and clearly related to the project work and keep in a portfolio

3

Evidences including log book are neat and accurate related to the project work and keep in a portfolio

2

Not all important evidences including log book are neither neat nor accurate related to the project work and keep in a portfolio

1

3

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The oral presentation should be assessed based on the assessment criteria below. Skill

Criterion

F: Oral Presentation ICT (Group assessment)

Description Students have positive and appropriate experiences in a wide range of ICT applications.

M ax M ark

2 2

1

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Students experience a limited range of ICT applications.

M ark Range

Presentation (Group assessment)

Holds attention of entire audience with the use of direct eye contact, seldom looking at notes. Speaker used techniques such as visual aids and props, anecdote, humour, surprising facts, direct audience participation.

2

The composition of the presentation elements exhibits creativity in effective delivery of the message.

2

Some eye contact was made, as entire report is read from notes.

Technique used to engage audience were minimal, or mainly ineffective. The composition of the presentation elements exhibits limited creativity.

13

1

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STPM 2014 Criterion Communications (Individual assessment)

Description

M ark Range

M ax M ark

Presenter spoke clearly and at a good pace to ensure audience comprehension. Delivery was fluent and expressive.

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Question answered with little difficulty. Very good knowledge of the project was demonstrated.

3

The presentation content was grammatically correct. Pronunciation and intonation is correct and confident.

3

Presenter usually spoke clearly to ensure audience comprehension. Delivery was usually fluent.

Most questions answered. Answers showed good knowledge and understanding of the project.

2

The presentation content was usually grammatically correct. Pronunciation and intonation is usually correct.

14

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STPM 2014 Criterion

Description

M ark Range

M ax M ark

Presenter occasionally spoke clearly and at a good pace.

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Not all questions could be answered. Questions answered with difficulty, and little knowledge of the project was demonstrated.

1

The presentation content was occasionally grammatically correct.

Pronunciation occasionally correct, but often hesitant and inaccurate.

15

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STPM CHEM I STRY

1.7 Summary of the Allocation of M ark for Experiments and Project

First term 1 2 3 4 5 Second term 6 7 8 9 10 Third term 11 12 13 Project Total mark

Skill A

Skill B

Skill C

Skill D

Skill E

A TP le x M T C an he m is try

Experiment

5 marks

Any 2 experiment ! 6 marks

9 marks

5 marks

6 marks

5 marks

6 marks

5 marks

6 marks

5 marks

6 marks

5 marks

6 marks

5 marks

Any 2 experiment ! 6 marks

5 marks

36 marks

5 marks for overall assessment per term

6 marks

5 marks for overall assessment per term

6 marks

5 marks

Any 2 experiment ! 6 marks

Skill F

9 marks

5 marks

6 marks

5 marks

6 marks

5 marks

6 marks

5 marks

6 marks

10 marks

6 marks

7 marks

75 marks

66 marks

31 marks

Overall total mark

225 marks

16

10 marks

7 marks 7 marks

STPM CHEM I STRY

1.8 Table of Summary of Experiments and Project

Experiment

Topic

Subtopic

Purpose

M ode of working

Report to be completed

First Term 1

Volumetric analysis

To determine the exact concentration of a monobasic acid, HX

Individually

In the laboratory

Acid base and redox

To determine the mass of sodium ethanedioate used to prepare a solution containing sodium ethanedioate and hydrated ethanedioic acid

Individually

In the laboratory

Purity and stoichiometry

To determine the purity of a sample of sodium sulphite

Individually

In the laboratory

Reaction kinetics

To determine the effect of temperature on the reaction rate

Individually

In the laboratory

Equilibrium and solubility

To determine the solubility product, Ksp, of MX2 and enthalpy change of solution, ǻH sol

Individually

In the laboratory

Thermochemistry

To determine the heat of reaction

Individually

In the laboratory

ElectrochemistryFaraday's Laws

To determine the percentage purity of copper metal by electrolysis

Individually

In the laboratory

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2

Stoichiometry

3

4

Physical Quantity

5

Second Term 6 7

Physical Quantity

17

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Experiment

Topic

8

Technique

STPM 2014

Subtopic

Purpose

M ode of working

Report to be completed

To determine the cations and anions of inorganic substances

Individually

In the laboratory

9

Qualitative analysis

To determine the cations and anions in inorganic salts

Individually

In the laboratory

10

TechniqueSynthesis

To determine the percentage of aluminium in a sample X by means of the preparation of a complex compound of aluminium with 8-hydroxyquinoline

Individually/ Group

In the laboratory

Qualitative analysis

To study the reactions of alcohols and carbonyl compounds

Individually

In the laboratory

12

Qualitative analysis

To study the reactions of Individually organic nitrogen compounds (amides, amines and their salts, amino acids and proteins)

In the laboratory

13

TechniqueSynthesis

To prepare a sample of 2-(4-hydroxyphenylazo) benzoic acid

Group

At home

To enable students to acquire knowledge and skills in chemistry using ICT as well as to develop soft-skills

Group

At the end of third term

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Qualitative analysis

Third Term 11

Project

Technique

Volumetric analysis/ Physical quantity/ Technique

18

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1.9 Preparation of Solutions For a 0.05 mol dm-3 solution of sodium ethanedioate, Na2C2O4, with a relative formula mass of 134.0, its concentration in g dm-3 can be prepared using the following equation. Concentration in g dm

3

= = =

molarity relative formula mass 0.05 134 6.7

Standard solutions of sulphuric acid, glacial ethanoic acid, and ammonia are prepared as follows:

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Step 1

mass and the specifications given in the table below, volume the volumes of reagents required for dilution can be calculated. By using the formula: Density =

Acid

Relative Molecular Mass

Density or Specific Gravity

Purity

HCl

36.5

1.18

36%

H2SO4

98.0

1.84

98%

HNO3

63.0

1.42

70%

H2O2 NH3

34.0 17.0

1.13

35% 25%

CH3COOH

60.0

0.88

0.91

1.05

99.5%

Example: To prepare 1 dm3 of 0.1 mol dm 3 solution of HCl, the volume of concentrated acid 3.65 100 required = = 8.59 cm3. 1.18 36 0.10 mol dm 3

Volume required/cm3

HCl

3.65

8.6

H2SO4

9.80

5.4

HNO3

6.30

6.3

H2O2

3.40

8.6

NH3

1.70

7.7

CH3COOH

6.00

5.7

Acid

19

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Step 2 For more accurate work, these solutions need to be standardised using a standard solution of sodium carbonate, Na2CO3. A standard solution of sodium carbonate can be prepared in the following way: A little anhydrous sodium carbonate is dried in an evaporating dish to eliminate all traces of moisture. The substance is then cooled in a desiccator. The amount required (5.3 g dm 3 for a 0.05 mol dm 3 solution) is then weighed, dissolved and made into a solution in a standard flask. Acid solutions are then standardised using this solution. Other concentrations of acid solutions can be prepared by diluting certain volumes of the acids and standardising them with the standard solution of sodium carbonate. Standard solution of sodium thiosulphate

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1.9.1

Standard solutions of sodium thiosulphate, Na2S2O3.5H2O, (relative molecular mass 248.0) cannot be prepared directly because of its salt's nature of absorbing water. For accurate work, a solution which is prepared directly will not give good results, e.g. problems which involve the determination of relative molecular mass or relative atomic mass. Prepared solutions of thiosulphate are normally standardised with potassium iodate, which will react with iodide in acid solution to liberate iodine. Potassium iodate is used because this compound is available in a pure state.

1.9.2

Standard solution of Fe2+ ions

To prepare this solution, use FeSO4.(NH4)2SO4.6H2O (relative molecular mass 392.0), not FeSO4.7H2O. Iron(II) sulphate is easily oxidised by air. In the preparation of this solution, the double salt FeSO4.(NH4)2SO4.6H2O needs to be dissolved in dilute sulphuric acid and made up to the required volume with distilled or deionised water.

1.9.3

I odine solution

Dissolve 20.0 g of iodate-free potassium iodide in 30 ± 40 cm3 distilled water. Weigh about 12.7 g iodine and transfer it to the 1 dm3 volumetric flask containing concentrated potassium iodide solution. Shake the mixture until all the iodine has dissolved. Make up the solution to the mark with distilled water.

1.9.4

Hydrogen peroxide solution

The strength of a solution of hydrogen peroxide is usually mentioned in µvolumes¶, e.g: µ20 - volume¶ hydrogen peroxide, µ100 - volume¶ hydrogen peroxide, etc. For a 20 - volume solution, 1 cm3 of hydrogen peroxide will decompose to yield 20 cm3 of oxygen at s.t.p. 2H2O2

2H2O + O2

68 g of hydrogen peroxide liberates 22.4 litres of oxygen at s.t.p. 1 g of hydrogen peroxide liberates

22.4 litres of oxygen at s.t.p. 68

1 litre of 20-volume hydrogen peroxide liberates 20 litres of oxygen at s.t.p. 1 litre of 20-volume hydrogen peroxide contains

20

20 6 = 60.8 g. 22 .4

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STPM 2014

Therefore, to prepare a 0.1 mol dm-3 solution of H2O2, about 5.6 cm3 of 20 - volume hydrogen peroxide must be diluted to make 1 litre. Other concentrations can be prepared by diluting suitable volumes of 20 - volume H2O2. Hydrogen peroxide solutions cannot be kept for long periods of time because of their strong tendency to decompose. Hence, hydrogen peroxide solutions for volumetric work must be standardised with a standard solution of potassium manganate(VII) before use. 1.9.5

I odine - potassium iodide solution (I odoform Test) Iodine dissolves sparingly in water. Its solution is prepared by adding 20.0 g potassium iodide and 10.0 g iodine in 80 cm3 distilled water. The mixture is stirred to form a deep brown solution. )HKOLQJV¶VROXWLRQ

ST A l PM ex T C an he m is try

1.9.6

Fehling's solution can be prepared as follows: (a)

)HKOLQJV¶6ROXWLRQ$ Dissolve 17.32 g copper(II) sulphate pentahydrate in 200 cm3 of distilled water and dilute the solution to 250 cm3.

(b)

)HKOLQJV¶6ROXWLRQ% Dissolve 86.5 g of sodium potassium tartarate and 35 g sodium hydroxide in 100 cm3 of distilled water and dilute the solution to 250 cm3.

To prepare the Fehlings¶solution, mix 2.5 cm3 )HKOLQJV¶6ROXWLRQ$DQGFP3 )HKOLQJV¶6ROXWLRQ% immediately before use.

1.9.7

Tollen's reagent

Add a drop of 2.5 mol dm±3 of sodium hydroxide solution to a 2 cm3 of 0.3 mol dm±3 of aqueous silver nitrate in a test tube. Add 3.0 mol dm±3 of ammonia drop by drop until all the precipitate (silver oxide) dissolves.

1.9.8

2,4-DinitrophenylhyGUD]LQHUHDJHQW%UDG\¶VUHagent)

Dissolving 3 g of 2,4-dinitrophenylhydrazine in 15 cm3 concentrated sulphuric acid. This solution is added with stirring to 20 cm3 of distilled water and 70 cm3 of 95% ethanol and filtered.

1.9.9

I ndicator solutions (a)

Methyl orange Dissolve 1 g of the solid in 1 dm3 of water.

(b)

Screened methyl orange Dissolve 1 g of methyl orange and 1.5 g of p-xylene cyanol in 500 cm3 of alcohol and dilute the solution to 1 dm3 with water.

(c)

Phenolphthalein Dissolve 1 g of the solid in 500 cm3 of alcohol and dilute the solution to 1 dm3 with water.

(d)

Starch indicator (usually 1%) Make a paste of 1 g of starch with cold water, then pour boiling water and make up to 100 cm3.

21

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1.10 Guidelines for Experiments Experiment 1 Notes for Teachers This experiment is to be conducted after the teacher has taught: (a)

Preparation of standard solutions

(b)

Skills involving acid-base titration

M aterials

ST A l PM ex T C an he m is try

A suitable monobasic acid is hydrochloric or ethanoic acid, about 150 cm3 per student.

A suitable base is sodium hydroxide or sodium carbonate with suitable mass as required by the student. A suitable indicator is phenolphthalein or methyl orange. Distilled water, about 250 cm3 per student.

Apparatus per student

250 cm3 volumetric flask and stopper

Electric balance 0.01 g or equivalent (common use) One 25 cm3 pipette and pipette filler

One 100 cm3 volumetric flask and stopper Two 50 cm3 burettes

One retort stand and clamp One white tile

One wash bottle filled with distilled water Spatula

Three titration flasks

Other suitable fittings and apparatus

Skills A, B, D, and E

Examples of skills A that can be seen are as follows: (a)

Reasonable quantities of substance used

(b)

Method of weighing to obtain an exact weight of substances

(c)

Technique of setting up, rinsing and filling up of the burette

(d)

Technique of rinsing, filling up and transferring the solution from the pipette into the titration flask

(e)

Addition of indicator at the appropriate time

(f)

Method of holding and shaking the titration flask during the titration process

(g)

Method of washing off the solution from the sides of the titration flask with distilled water before reaching the end-point 22

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Experiment 2 Notes for Teachers

M aterials KA 1 is a solution containing 3.00 g of sodium ethanedioate, Na2C2O4, and 4.00 g hydrated ethanedioic acid, H2C2O4.2H2O, per dm3, about 250 cm3 per student. KA 2 is a solution containing 3.50 g potassium manganate(VII), KMnO4, per dm3, about 120 cm3 per student.

ST A l PM ex T C an he m is try

KA 3 is a solution containing 4.00 g sodium hydroxide per dm3, about 120 cm3 per student. KA 4 is 1.00 mol dm-3 sulphuric acid, about 120 cm3 per student. Phenolphthalein as an indicator.

Apparatus per student

Two 25 cm3 pipettes and pipette fillers Two 50 cm3 burettes Six titration flasks

Two retort stands and clamps

One 50 cm3 measuring cylinder Two white tiles

One wash bottle filled with distilled water

One thermometer 0 C ± 100 C (± 1.0 C)

Skills A, B, C and E

Examples of skills A that can be seen are as follows: (a)

Technique of setting up, rinsing and filling up of the burette

(b)

Technique of rinsing, filling up and transferring the solution from the pipette into the titration flask

(c)

Addition of indicator at the appropriate time

(d)

Method of holding and shaking the titration flask during the titration process

(e)

Method of washing off the solution from the sides of the titration flask with distilled water before reaching the end-point

(f)

Technique of using measuring cylinder to measure volume of solution

(g)

Technique of heating the solution before titration

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Experiment 3 Notes for Teachers

M aterials KA 1 is a 0.025 mol dm 3 iodine solution prepared by dissolving 6.35 g of iodine in 10% solution of potassium iodide per dm3, about 250 cm3 per student. KA 2 is a solution containing 12.41 g of sodium thiosulphate per dm3, about 200 cm3 per student.

ST A l PM ex T C an he m is try

KA 3 is a solution containing 3.15 g of anhydrous sodium sulphite, Na2SO3, per dm3, about 150 cm3 per student. KA 4 is 2 g sodium hydrogencarbonate, about 8 g per student. Starch as an indicator.

Apparatus per student

One 25 cm3 pipette and pipette filler One 50 cm3 pipette

Three titration flasks One 50 cm3 burette

One retort stand and clamp One white tile

One wash bottle filled with distilled water

Skills A, B, C, and E

Examples of skills A that can be seen are as follows: (a)

Technique of setting up, rinsing and filling up of the burette

(b)

Technique of rinsing, filling up and transferring the solution from the pipette into the titration flask

(c)

Addition of indicator at the appropriate time

(d)

Method of holding and shaking the titration flask during the titration process

(e)

Method of washing off the solution from the sides of the titration flask with distilled water before reaching the end-point

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Experiment 4 Notes for Teachers

M aterials KA 1 is a solution containing 24.90 g of potassium iodide per dm3, about 150 cm3 per student. KA 2 is a 0.5% starch solution, about 50 cm3 per student.

ST A l PM ex T C an he m is try

KA 3 is a solution containing 12.41 g of sodium thiosulphate per dm3, about 50 cm3 per student. KA 4 is a solution containing 8.60 cm3 of hydrogen peroxide (35%) per dm3, about 300 cm3 per student. KA 5 is a solution containing 54.0 cm3 of concentrated sulphuric acid per dm3, about 150 cm3 per student. Ice and hot water are used as water bath and also to obtain different temperatures. Distilled water, about 150 cm3 per student.

Apparatus per student

One 25 cm3 pipette and pipette filler One 10 cm3 measuring cylinder One 50 cm3 measuring cylinder One 50 cm3 burette

One retort stand and clamp One conical flask One stopwatch

One 150 cm3 beaker

One thermometer 0 C ± 100 C ( 1.0 C) One wash bottle filled with distilled water One white tile

Skills A, B, C, and E

Examples of skills A that can be seen are as follows: (a)

Technique of obtaining and maintaining the required temperatures

(b)

Accuracy in noting the time when the blue colour appears

Examples of skills B and C that can be seen are as follows: (a)

Recording time and temperature in the correct spaces

(b)

Plotting of graph from the information obtained

(c)

Interpretation of the graph plotted 25

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Experiment 5 Notes for Teachers

M aterials KA 1 is solution containing 33.10 g of lead(II) nitrate per dm3, about 150 cm3 per student. KA 2 is solution containing 29.25 g of sodium chloride per dm3, about 100 cm3 per student.

ST A l PM ex T C an he m is try

Apparatus per student Two burettes

Five boiling tubes

One thermometer 0 ºC ± 100 ºC (± 1.0 ºC) Two 250 cm3 beakers

Two retort stands and clamps One test-tube holder One water bath

Skills A, B, C and E

Examples of skills B and C that can be seen are as follows: (a)

Recording of volume and temperature in the correct spaces

(b)

Plotting of graph from the information obtained

(c)

Interpretation of the graph obtained

26

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Experiment 6 Notes for Teachers ± M aterials KA 1 is a solution containing 172 cm3 of concentrated hydrochloric acid per dm3, about 100 cm3 per student. KA 2 is 2.00 g to 2.40 g of solid anhydrous sodium carbonate in a stoppered test-tube; one test-tube of KA 2 per student.

ST A l PM ex T C an he m is try

KA 3 is 2.70 g to 3.10 g of sodium hydrogencarbonate in a stoppered test-tube; one testtube of KA 3 per student.

Apparatus per student

One 50 cm3 burette

One retort stand and clamp

One plastic/polystyrene cup

One thermometer 0 C ± 110 C ( 0.2 C) One wash bottle filled with distilled water Electric balance 0.01 g (common use)

Skills A, B, C, and E

Examples of skills B that can be seen are as follows: (a)

Measurement of the initial temperature is only carried out when the temperature is stable

(b)

Correct method of weighing to obtain an exact weight of KA 2

(c)

Weights to be recorded to the nearest 0.01 g in the correct spaces

(d)

Temperatures to be recorded to the nearest 0.2 C in the correct spaces

27

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Experiment 7 Notes for Teachers

M aterials Solution containing 250 g of CuSO4.5H2O per dm3, about 300 cm3 per student. Propanone, about 100 cm3 per student. Distilled water, about 200 cm3 per student.

ST A l PM ex T C an he m is try

Apparatus per student

One 100 cm3 measuring cylinder One 250 cm3 beaker

Two pieces of copper plates measuring 5 cm

4 cm

0.2 cm

Five connecting wires with crocodile clips One ammeter, 0 A

3A

One rheostat, 11 One switch

Four dry cells or source of direct current 6 V One stopwatch

Hair dryer (common use) Electric balance

0.01 g (common use)

One wash bottle filled with distilled water Other suitable fittings and apparatus

Skills A, B, D and E

Examples of skill D that can be seen are as follows: (a)

Neat and proper planning in following common procedures

(b)

Selecting, setting up of apparatus, and using of materials correctly and completely

(c)

Obtaining and recording of the masses of both the copper plates at the anode and the cathode before and after the electrolysis process

(d)

Time planning to be compatible with the experiment

28

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Experiment 8 Notes for Teachers (a)

The teacher has to supply different salts to each of the classes taught.

(b)

The teacher has to supply a different salt each year to the students.

M aterials KA 1, solid MgS2O3 or MgSO3 or CuSO3 or Pb(CH3COO)2 or Ca(CH3COO)2 KA 2, a mixture of solids Al2(SO4)3 and (NH4)2SO4 or a mixture of solids Zn(NO3)2 and NH4NO3

ST A l PM ex T C an he m is try

Common acids (concentrated and dilute)

Common alkalis (concentrated and dilute)

Aqueous solution of iron(III) chloride, approximately 50 g dm

3

Dissolve 135 g of solid iron(III) chloride in distilled water containing 20 cm3 of concentrated hydrochloric acid and make up the volume of solution to 1 dm3. Aqueous solution of ammonium chloride, approximately 50 g dm Aqueous solution of silver nitrate, approximately 50 g dm

3

3

Aqueous solution of disodium hydrogen phosphate, approximately 50 g dm Aqueous solution of potassium chromate(VI), approximately 50 g dm Aqueous solution of potassium iodide, approximately 50 g dm

3

3

3

Aqueous solution of sodium ethanoate, approximately 50 g dm

3

Aqueous solution of sodium carbonate, approximately 50 g dm

3

Apparatus per student

One test-tube rack with six test tubes

One hard glass test-tube with delivery tube One test-tube holder One spatula

One filter funnel and two pieces of filter paper One teat pipette

One Bunsen burner

Red and blue litmus papers Wooden splint

One wash bottle filled with distilled water

Skills A, B, C, and E

Examples of skills B and C that can be seen are as follows: (a)

Correct observations for each of the tests done

(b)

Correct deductions which are consistent with correct observations 29

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Experiment 9 Notes for Teachers (a)

The teacher has to supply different salts and other suitable reagents to each of the classes taught.

(b)

The teacher has to supply different salts and other suitable reagents each year to the students.

M aterials KA 1, a mixture of solids KI and KNO3 or a mixture of solids KBr and KNO3

ST A l PM ex T C an he m is try

Common acids (concentrated and dilute)

Common alkalis (concentrated and dilute) 'HYDUGD¶VDOOR\

Aqueous solution of silver nitrate, approximately 50 g dm

3

Aqueous solution of iron(II) sulphate, approximately 50 g dm

3

Aqueous solution of lead(II) ethanoate , approximately 50 g dm

3

Aqueous solution of ammonium chloride, approximately 50 g dm

3

1,1,1-trichloroethane (test for halogens) Other suitable reagents

Apparatus per student

One test-tube rack and six test-tubes

One hard glass test-tube and delivery tube One test-tube holder One spatula

One filter funnel and two pieces of filter paper One teat pipette

One Bunsen burner

Red and blue litmus papers Wooden splint

One wash bottle filled with distilled water

Skills A, B, D, and E

Examples of skill B that can be seen are as follows: Tests on KA (a)

Correct observations for each of the tests done

(b)

Correct deductions which are consistent with correct observations

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Experiment 10 Notes for Teachers (a)

The students are required to submit the product of the experiment together with their reports.

M aterials KA 1 is a solution of 8-hydroxyquinoline prepared by dissolving 2.00 g of 8-hydroxyquinoline in 100 cm3 of 2 mol dm 3 ethanoic acid, about 50 cm3 per student.

ST A l PM ex T C an he m is try

KA 2 is a solution containing 154.00 g of CH3COONH4 per dm3, about 100 cm3 per student. KA 3 is a potassium alum, KAl(SO4)2 .12H2O, about 0.25 g to 0.30 g per student.

KA 4 is a solution containing 170 cm3 of concentrated hydrochloric acid per dm3, about 10 cm3 per student. Distilled water, about 200 cm3 per student. Ice cubes which are used as water bath.

Apparatus per student

Electric balance 0.01 g (common use) One 250 cm3 beaker One Bunsen burner

One tripod stand and wire gauze

One thermometer 0 C to 100 C One crucible and lid

One filter funnel and filter paper One teat pipette

One 250 cm3 conical flask

One wash bottle filled with distilled water Oven (common use)

Magnetic stirrer, one per four students One 50 cm3 measuring cylinder

Skills A, B, C, and E

Examples of skill A that can be seen are as follows: (a)

Correct technique of weighing

(b)

Ensuring that all product are removed from the filter paper

(c)

Ensuring that the temperature of the oven is 120 C

31

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Experiment 11 Notes for Teachers (a)

The iodine potassium solution, Tollen's reagent and Brady's reagent should be freshly prepared before the experiment begins. Fehlings' solution A and Fehlings' solution B should be mix immediately before use with the unknown.

M aterials KA 1, absolute ethanol, about 10 cm3 per student KA 2, propanal or acetone, about 10 cm3 per student

ST A l PM ex T C an he m is try

Concentrated and 1 mol dm 3 sulphuric acid Glacial ethanoic acid

1 mol dm-3 sodium hydroxide solution

Acidified of potassium manganate(VII) solution, approximately 3 g dm

3

Iodine-potassium iodide solution (Iodoform Test) FHKOLQJV¶VROXWLRQ 7ROOHQV¶UHDJHQW

2,4 'LQLWURSKHQ\OK\GUD]LQHVROXWLRQ%UDG\¶VUHDJHQW

Apparatus per student

One test-tube rack and six test-tubes One test tube holder One Bunsen burner

One 250 cm3 beaker

One wash bottle filled with distilled water One teat pipette /dropper

Skills A, B, C and E

Examples of skills B and C that can be seen are as follows: (a)

Correct observations for each of the tests done

(b)

Correct observations for each of the tests done

(c)

Correct deductions which are consistent with the observations

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Experiment 12 Notes for Teachers (a)

KA 2 is smelly, with an unpleasant odour and should be administered in a fume chamber.

M aterials KA 1, 2.0 g ethanamide KA 2, 5 cm3 of 1-butanamine Common acids (concentrated and dilute)

ST A l PM ex T C an he m is try

Common alkalis (concentrated and dilute) Bromine water

Dissolve bromine liquid in water to make a saturated solution Sodium nitrite

5% Sodium hydrogencarbonate solution Propanone Ice cubes

Universal indicator

Apparatus per student

One test-tube rack and six test-tubes

One hard glass test tube and delivery tube One test-tube holder One spatula

One teat pipette

One Bunsen burner

Blue and red litmus paper Wooden splinter

One wash bottle filled with distilled water One 250 cm3 beaker

Skills A, B, C and E

Examples of skill A that can be seen are as follows: (a)

Reagents to be added slowly so that all the stages of observation can be recorded

Examples of skills B and C that can be seen are as follows: (a)

Correct observations for each of the tests done

(b)

Correct deductions which are consistent with the observations

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Experiment 13 Notes for Teachers (a)

The students are required to submit the product of the experiment together with their reports.

(b)

Since phenol is a highly hygroscopic substance (absorbing water from the air), the stock alkaline solution of phenol must be prepared immediately after the bottle containing phenol is open and the solution is kept in the big amber glass bottles.

(c)

Common salt may be added to the ice to lower the temperature of ice water bath to 5 °C.

ST A l PM ex T C an he m is try

M aterials KA 1 is solid 2-aminobenzoic acid, about 3.4 g per group.

KA 2 is a solution containing 140.0 cm3 of concentrated hydrochloric acid (37 wt.%) per dm3, about 65 cm3 per group. KA 3 is solid sodium nitrite, about 1.9 g per group.

KA 4 is solution prepared by dissolving 54 g of sodium hydroxide in about 900 cm3 of distilled water followed by dissolving 28.24 g of phenol, then water is added to a 1 dm3 mark; about 85 cm3 per group. If phenol in a liquid form, it is estimated that there is 8 g phenol in 100 cm3 in the liquid solution. To prepare the KA4 solution, we need to dissolve 54 g of sodium hydroxide in about 900 cm3 of distilled water followed by dissolving 353 cm3 of phenol, then water is added to a 1 dm3 mark; about 85 cm3 per group. KA 5 is a solution containing 330.0 cm3 of concentrated hydrochloric acid (37 wt.%) per dm3, about 35 cm3 per group. Distilled water, about 250 cm3 per group. Acetone, about 70 cm3 per group. Sodium chloride (common salt)

Ice cubes which are used as water bath.

Apparatus per group

Electric balance ± 0.01 g (common use) One 125 cm3 conical flask

Two 100 cm3 graduated cylinders One 100 cm3 beaker One PVC basin

One teat pipette

One teat pipette rubber bulb

One thermometer 0 to 100 C

One glass, spoon-paddle ends spatula, about 30 cm long One wash bottle filled with distilled water

One Buchner filter funnel, its conical flask and filter paper A watch glass/evaporating dish 34

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Skills A, B, C and E Examples of skill A that can be observed are as follows: Correct method employed in weighing

(b)

Correct method employed in handling the Buchner filtration apparatus

(c)

Correct technique employed in carrying out the crystallization and drying of crystals

ST A l PM ex T C an he m is try

(a)

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1.11 List of Apparatus and M aterials 1.11.1 List of Apparatus and M aterials by Experiments Apparatus/M aterials 250 cm3 volumetric flask and stopper Electric balance 0.01 g 25 cm3 pipette and pipette filler 100 cm3 flask and stopper 50 cm3 burette Retort stand and clamp White tile Wash bottle filled with distilled water Titration flask 150 cm3 hydrochloric or ethanoic acid Sodium hydroxide or sodium carbonate Phenolphthalein or methyl orange 250 cm3 distilled water 25 cm3 pipette and pipette filler 50 cm3 burette Titration flask Retort stand and clamp 50 cm3 measuring cylinder White tile Wash bottle filled with distilled water Thermometer 0 C ± 100 C ( 1.0 C) Sodium ethanedioate Hydrated ethanedioic acid Potassium manganate(VII) Sodium hydroxide Sulphuric acid Phenolphthalein 25 cm3 pipette and pipette filler 50 cm3 pipette Titration flask 50 cm3 burette Retort stand and clamp White tile Wash bottle filled with distilled water Iodine solution Potassium iodide Sodium thiosulphate Anhydrous sodium sulphite Sodium hydrogencarbonate Starch

Quantity used common use 1 1 2 1 1 1 3

ST A l PM ex T C an he m is try

Experiment no. (M ode of working)

1 (Individual)

2 (Individual)

3 (Individual)

36

2 2 6 2 1 2 1 1

1 1 3 1 1 1 1

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RESTRI CTED CHEM I STRY PRACTI CAL Experiment no. (M ode of working)

Apparatus/M aterials 150 cm3 beaker Wash bottle filled with distilled water 50 cm3 burette Stopwatch White tile 250 cm3 conical flask Retort stand and clamp 25 cm3 pipette and pipette filler 10 cm3 measuring cylinder 50 cm3 measuring cylinder Thermometer 0 C 100 C ( 1.0 C) Distilled water, hot water, and ice Sulphuric acid Hydrogen peroxide Potassium iodide Sodium thiosulphate Starch 50 cm3 burette Boiling tube Thermometer 0 C ± 100 C ( 1.0 C) Water bath 250 cm3 beaker Retort stand and clamp Test-tube holder Lead(II) nitrate Sodium chloride 50 cm3 burette Wash bottle filled with distilled water Plastic/polystyrene cup Electric balance ( 0.01 g) Retort stand and clamp Thermometer 0 C 110 C ( 0.2 C) Hydrochloric acid Sodium hydrogen carbonate Anhydrous sodium carbonate

Quantity used 1 1 1 1 1 1 1 1 1 1 1

ST A l PM ex T C an he m is try

4 (Individual)

STPM 2014

5 (Individual)

6 (Individual)

37

2 5 1 1 2 2 1

1 1 1 Common use 1 1

RESTRI CTED

RESTRI CTED CHEM I STRY PRACTI CAL Experiment no. (M ode of working)

Apparatus/M aterials Ammeter 0 A 3 A ( 0.1 A) 250 cm3 beaker Wash bottle filled with distilled water Stopwatch Copper plate measuring 5 cm 4 cm 0.2 cm Hair dryer Electric balance ( 0.01 g) 11 rheostat Dry cell (source of direct current 6 V) Connecting wire with crocodile clips 100 cm3 measuring cylinder Switch Distilled water Copper(II) sulphate pentahydrate Propanone Test-tube rack with six test tubes Hard glass test-tube with delivery tube Test-tube holder Spatula Filter funnel and two pieces of filter paper Teat pipette Bunsen burner Red and blue litmus papers Wooden splint Wash bottle filled with distilled water Magnesium thiosulphate(VI) or magnesium sulphite or copper sulphite or calcium ethanoate or lead(II) ethanoate Aluminium sulphate or ammonium sulphate or zinc nitrate or ammonium nitrate Nitric acid Ammonia Hydrochloric acid Sodium hydroxide Iron(III) chloride Ammonium chloride Silver nitrate Disodium hydrogen phosphate Potassium chromate(VI) Potassium iodide Sodium carbonate Sodium ethanoate

Quantity used 1 1 1 1 2 Common use Common use 1 4 5 1 1

ST A l PM ex T C an he m is try

7 (Individual)

STPM 2014

8 (Individual)

38

1 1 1 1 1 1 1

1

RESTRI CTED

RESTRI CTED CHEM I STRY PRACTI CAL Apparatus/M aterials Test-tube rack and six test-tubes Hard glass test-tube and delivery tube Test-tube holder Spatula Filter funnel and two pieces of filter paper Teat pipette Bunsen burner Red and blue litmus papers Wooden splint Wash bottle filled with distilled water Hydrochloric acid Nitric acid Ammonia Sodium hydroxide 'HYDUGD¶VDOOR\ Silver nitrate Iron(II) sulphate Lead(II) ethanoate Ammonium chloride 1,1,1-trichloroethane Other reagents for testing iodine and nitrate ions Potassium iodide Potassium nitrate Copper(II) carbonate or magnesium carbonate or calcium carbonate or manganese carbonate or nickel(II) carbonate or barium chloride or magnesium chloride or calcium chloride 250 cm3 beaker Wash bottle filled with distilled water 250 cm3 conical flask Oven Electric balance ( 0.01 g) Magnetic stirrer Teat pipette Bunsen burner Refrigerator Filter funnel and filter paper Crucible with lid Tripod and wire gauze 50 cm3 measuring cylinder

Quantity used 1 1 1 1 1 1 1

ST A l PM ex T C an he m is try

Experiment no. (M ode of working)

STPM 2014

9 (Individual)

10 (Individual/ Group)

39

1

1 1 1 Common use Common use 1 per 4 persons 1 1 Common use 1 1 1 1

RESTRI CTED

RESTRI CTED CHEM I STRY PRACTI CAL Apparatus/M aterials Thermometer 0 C 100 C ( 1.0 oC) Ethanoic acid Hydrochloric acid Ice Ammonium ethanoate 8-hydroxyquinoline Potassium alum, KAl(SO4)2.12H2O Test-tube rack and six test tubes Test-tube holder Bunsen burner 250 cm3 beaker Wash bottle filled with distilled water Teat pipette/Dropper Absolute ethanol Propanal Propanone Butanone or 1-butanol Sulphuric acid 99.5% ethanoic acid Sodium hydroxide Potassium manganate(VII) Potassium iodide Iodine Silver nitrate Ammonia Copper(II) sulphate pentahydrate Sodium potassium tartrate tetrahydrate 2,4-dinitrophenylhydrazine 95% ethanol

Quantity used 1

1 1 1 1 1 1

ST A l PM ex T C an he m is try

Experiment no. (M ode of working)

STPM 2014

11 (Individual)

40

RESTRI CTED

RESTRI CTED CHEM I STRY PRACTI CAL Apparatus/M aterials Test-tube rack and six test tubes Hard glass test-tube and delivery tube Test-tube holder Spatula Teat pipette Bunsen burner Red and blue litmus papers Wooden splinter Wash bottle filled with distilled water 250 cm3 beaker Ethanamide 1-butanamine Sulphuric acid Hydrochloric acid Sodium hydroxide Bromine water Sodium nitrite

Quantity used 1 1 1 1 1 1

1 1

ST A l PM ex T C an he m is try

Experiment no. (M ode of working)

STPM 2014

12 (Individual)

13 (Group)

Sodium hydrogencarbonate Propanone Ice Universal indicator Electric balance ( 0.01 g) 125 cm3 conical flask 100 cm3 graduated cylinder 100 cm3 beaker PVC basin Teat pipette Teat pipette rubber bulb Thermometer 0 C 100 C ( 0.01) Glass, spoon-paddle ends spatula Wash bottle filled with distilled water Buchner filter funnel Conical flask Filter paper Watch glass/evaporating dish 2-aminobenzoic acid Hydrochloric acid Sodium nitrite Sodium chloride Sodium hydroxide Phenol Ice 41

common use 1 2 1 1 1 1 1 1 1 1 1 1 1

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1.11.2 List of apparatus and materials by experiments No 1

Ammeter 0 A 3 A ( 0.1 A) 100 cm3 beaker 150 cm3 beaker 250 cm3 beaker

Quantity used

Experiment no.

M ode of working

1

7

Ind

1 1 1 2 1 1 1 5 1 1 1 1 1 1 2 2 1 1 2 1 5 1 1 1 1 2

13 4 7 5 10 11 12 5 13 8 9 10 11 12 1 2 3 4 5 6 7 13 4 10 1 1 7

Group Ind Ind Ind Ind/Group Ind Ind Ind Group Ind Ind Ind/Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Group Ind Ind/Group Ind Ind Ind

1 1 1 1 1 1 2 4

10 4 2 4 10 7 13 7

Ind/Group Ind Ind Ind Ind/Group Ind Group Ind

ST A l PM ex T C an he m is try

2 3 4

Apparatus

5 6 7

Boiling tube Buchner filter funnel Bunsen burner

8

50 cm3 burette

9 10 11

Connecting wire with crocodile clip 125 cm3 conical flask 250 cm3 conical flask

12 13 14

100 cm3 flask and stopper 250 cm3 volumetric flask and stopper

15 16 17

18 19 20

Copper plate 5 cm 4 cm 0.2 cm Crucible with lid 10 cm3 measuring cylinder 50 cm3 measuring cylinder

100 cm3 measuring cylinder 100 cm3 graduated cylinder Dry cell 1.5 V (source of direct current 6 V)

1RWH³&´ &RPPRQXVH,QG ,QGLYLGXDO

42

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STPM 2014

Apparatus Electric balance ( 0.01 g)

22

Filter funnel

23

Filter paper

24 25 26

Glass, spoon-paddle ends spatula Hair dryer Hard glass test-tube and delivery tube

27 28

Magnetic stirrer Oven

29

Pipette filler

30

25 cm3 pipette

31 32 33 34

50 cm3 pipette Plastic/polystyrene cup PVC basin Red and blue litmus papers

35 36

Refrigerator Retort stand and clamp

37

11

Experiment no.

M ode of working

C C C C C 1 1 1

1 6 7 10 13 8 9 10 8 9 10 13 13 7 8 9 12 10 10 13 1 2 3 4 1 2 3 4 3 6

Ind Ind Ind Ind/Group Group Ind Ind Ind/Group Ind Ind Ind/Group Group Ind Ind Ind Ind Ind Ind/Group Ind/Group Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind

13 8 9 12 10 1 2 3 4 5 6 7

Group Ind Ind Ind Ind/Group Ind Ind Ind Ind Ind Ind Ind

ST A l PM ex T C an he m is try

21

Quantity used

1 C 1 1 1 1 C C 1 2 1 1 1 2 1 1 1 1 1

C 1 2 1 1 2 1 1

rheostat

1RWH³&´ &RPPRQXVH,QG ,QGLYLGXDO 43

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Apparatus Spatula

39

Stopwatch

40 41

Switch Teat pipette

Experiment no. 8 9 12 4 7 7 8 9 10 11 12 13

M ode of working Ind Ind Ind Ind Ind Ind Ind Ind Ind/Group Ind Ind Ind

1 1 1 1 1 1 1 1 1 3 6 3 1 1 1 1 1 1

13 8 9 11 12 8 9 11 12 1 2 3 2 4 5 10 13 6

Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind/Group Group Ind

1 1 1 1 1 1 1 1 1 1 1 1 1

10 1 2 3 4 6 7 8 9 10 11 12 13

Ind/Group Ind Ind Ind Ind Ind Ind Ind Ind Ind/Group Ind Ind Group

ST A l PM ex T C an he m is try

38

Quantity used 1 1 1 1 1 1 1 1 1 1 1 1

42 43

Teat pipette rubber bulb Test-tube holder

44

Test-tube rack and six test-tubes

45

Titration flask

46

Thermometer 0 oC ! 100 oC ( 1.0 oC)

47

Thermometer 0 oC ! 110 oC ( 0.2 oC)

48 49

Tripod and wire gauze Wash bottle

1RWH³&´ &RPPRQXVH,QG ,QGLYLGXDO 44

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Apparatus

Quantity used

Experiment no.

M ode of working

Watch glass/evaporating dish Water bath White tile

1 1 1 2 1 1

13 5 1 2 3 4

Ind Ind Ind Ind Ind Ind

53

Wooden splint

1 1 1

8 9 12

Ind Ind Ind

ST A l PM ex T C an he m is try

50 51 52

!

! ! ! ! ! ! ! ! !

1RWH³&´ &RPPRQXVH,QG ,QGLYLGXDO

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

45

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1.11.3 List of chemicals by experiments No

Quantity used

Chemical Absolute ethanol 2-aminobenzoic acid Aluminium sulphate Ammonia

5

Ammonium chloride

M ode of working

11 13 8 8 9 11 8 9 10 8 8 3 9 12 12 11 9 9 8 9 7 11 8 9 11 8 1 10 12 11 11 4 2 1 6 8 9 10 12 13

Ind Group Ind Ind Ind Ind Ind Ind Ind/Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind/Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind/Group Ind Group

ST A l PM ex T C an he m is try

1 2 3 4

Experiment no.

6 7 8 9 10 11 12 13 14 15 16 17 18

Ammonium ethanoate, CH3COONH4 Ammonium nitrate Ammonium sulphate Anhydrous sodium sulphite Barium chloride Bromine water Butanamine Butanone or 1-butanol Calsium carbonate Calsium chloride Calsium ethanoate Copper(II) carbonate Copper(II) sulphate pentahydrate

19 20 21 22 23

Copper sulphite 'HYDUGD¶VDOOR\ 2,4-Dinitrophenylhydrazine Disodium hydrogen phosphate Ethanoic acid

24 25

Ethanamide 99.5% Ethanoic acid 95% Ethanol Hot water and ice Hydrated ethanedioic acid Hydrochloric acid

26 27 28

46

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STPM 2014 Quantity used

Chemical Hydrogen peroxide 8-Hydroxyquinoline Ice

32

Iodine

33 34 35

Iron(II) sulphate Iron(III) chloride Lead(II) ethanoate

36 37 38 39 40 41 42 43 44

Lead(II) nitrate Manganese carbonate Magnesium carbonate Magnesium chloride Magnesium sulphite Magnesium tiosulphate(VI) Methyl orange Nickel(II) carbonate Nitric acid

45 46

Phenol Phenolphthalein

47 48

Potassium alum, KAl(SO4)2.12H2O Potassium iodide

49 50

Potassium chromate(VI) Potassium manganate(VII)

51 52 53

Potassium nitrate Propanal Propanone

54

Silver nitrate

M ode of working

4 10 10 12 13 3 11 9 8 8 9 5 9 9 9 8 8 1 9 8 9 13 1 2 10 3 4 8 9 11 8 2 11 9 11 7 11 12 8 9 11

Ind Ind/Group Ind/Group Ind Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Group Ind Ind Ind/Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind

ST A l PM ex T C an he m is try

29 30 31

Experiment no.

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STPM 2014 Quantity used

Chemical Sodium ethanedioate Sodium ethanoate Sodium hydrogen carbonate

58

Sodium carbonate

59

Sodium hydroxide

60 61

Sodium chloride Sodium nitrite

62 63

Sodium potassium tartrate tetrahydrate Sodium tiosulphate

64

Starch

65

Sulphuric acid

66 67 68

1,1,1-trichloroethane Universal indicator Zinc nitrate

M ode of working

2 8 3 6 12 1 6 8 1 2 8 9 11 12 13 5 12 13 11 3 4 3 4 2 4 11 12 9 12 8

Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Group Ind Ind Group Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind Ind

ST A l PM ex T C an he m is try

55 56 57

Experiment no.

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STPM 2014 Appendix A 6WXGHQW¶V5HFRUG Form

Name of school/institute Name of student Centre no./Index no. Skill Study term First

Second

Third

Date

A TP le x M T C an he m is try

SCHOOL-BASED ASSESSM ENT OF PRACTI CAL CHEM I STRY (PAPER 962/4) STPM 2014

Experiment

S

I/C no.

/

Mark for skill assessed A B C D 7HDFKHU¶V 7HDFKHU¶V 0RGHUDWRU¶V 7HDFKHU¶V 0RGHUDWRU¶V 7HDFKHU¶V 0RGHUDWRU¶V mark mark mark mark mark mark mark

E 7HDFKHU¶V mark

7HDFKHU¶V mark

F 0RGHUDWRU¶V mark

Notes

Exp 1 Exp 2 Exp 3 Exp 4 Exp 5 Exp 6 Exp 7 Exp 8 Exp 9 Exp10 Exp 11 Exp 12 Exp 13 Project Total mark Overall total mark

7($&+(5¶6'(&/$5$7,21 I certify that the marks and details recorded above are true. «««««««««««««««««««««««« Name: Date: Contact number (H/P): Contact number (O):

02'(5$725¶6'(&/$5$7,21 I certify that the marks and details recorded above are true. «««««««««««««««««««««««« Name: Date: Contact number (H/P): Contact number (O):

49

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STPM 2014 Appendix B

A TP le x M T C an he m is try

SCHOOL-BASED ASSESSM ENT FOR PRACTI CAL CHEM I STRY (PAPER 962/4) EXPERI M ENT REPORT STPM 2014

1DPHRIVFKRROFROOHJH««««««««««««««««««««««««««««««««««««« Experiment Number

Topic

Centre nuPEHU««««««««««

Problem/Modification/Suggestion/Comment

Note: If there is no problem/modification/suggestion/comment for a certain experiment, please wriWH³NONE´ 50

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STPM 2014

Part 26WXGHQW¶V0DQXDOIRUPractical Chemistry 2.1 I ntroduction MEC has determined 13 compulsory experiments and one project to be carried out by students which will be assessed by the teacher in three respective terms.

2.1.2

Experiments and project are to be carried out either individually or in groups as recommended in the Table of Summary of Experiments and Project on pages 55.

2.1.3

The assessment of experimental skills should be done while the student is carrying out the experiment and also on the student¶VSUDFWLFDOZRUNUHSRUW7KHDVVHVVPHQWIRU the project should be done according to the project report and the oral presentation made by students.

ST A l PM ex T C an he m is try

2.1.1

2.1.4

For a student who is absent for an experiment with reason, the teacher can fix another date for the students to carry out the experiment.

2.1.5

Students may write their practical work and project reports in either English or Bahasa Melayu. The practical work reports is to be submitted to the teacher on the same day the experiment is carried out unless otherwise stated. (Refer to the Table of Summary of Experiments and Project on pages 55). Practical work reports which are not submitted RQWKHGD\RIWKHH[SHULPHQWDUHWREHDZDUGHGµ¶PDUN

2.1.6

Practical work reports which can be completed at home are to be submitted to the teacher not later than 3 days from the date of the experiment. A penalty of 2 marks is to be imposed for the reports submitted late to the teacher. Practical work reports which are submitted laWHUWKDQGD\VIURPWKHGDWHRIWKHH[SHULPHQWDUHWREHDZDUGHGµ¶ mark.

2.1.7

The teacher is required to set the dateline for the submission of project in the specified date at the end of third term. A penalty of 2 marks is to be imposed for the reports submitted late to the teacher.

2.1.8

The oral presentation for the project work should be carried out by the teachers after the assessment of the project report of all students. If the teacher suggests that changes are required towards the project report after the oral presentation, the student needs to correct the project report.

2.1.9

For a student who has transferred to another school, the previous school is to send the VWXGHQW¶VUHSRUWVDQGWKH6WXGHQW5HFRUGForm which is partially completed and signed by the subject teacher, to the student¶VQHZVFKRRO

2.2 Assessment of Practical Work and Project 2.2.1

Students are to be assessed based on the following skills:

Skill A: Use of techniques and manipulation of apparatus and materials

To get maximum marks, students need to exhibit psychomotor skills in manipulating the apparatus and materials skillfully and efficiently to a suitable degree of accuracy without assistance.

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Skill B: Observations, measurements, and recording To get maximum marks, students need to make observations accurately, record readings and data completely, and perform calculations to a suitable degree of accuracy. Skill C: I nterpretation of experimental observations and data To get maximum marks, students need to answer all the questions given or make deductions correctly. Skill D: Design and planning of investigation

ST A l PM ex T C an he m is try

To get maximum marks, students need to plan their experiment or project neatly, completely, and efficiently according to the format they have learned and to complete the experiment or project within a specified period of time and/or they are able to modify the planning based on their experience. Skill E: Scientific and critical attitudes

Among the attitudes expected of students are self-reliant, trustworthy, fair, curious, inquisitive, having initiative, innovative, receptive to new ideas, cooperative, and caring for the environment. Skill F: Oral presentation

7R JHW PD[LPXP PDUNV VWXGHQW¶V QHHG WR KDYH SRVitive and appropriate experiences in a wide range of ICT applications, and exhibit a good technique of presentation skills and communication skills.

2.2.2

The school will be notified of the theme of the project for the current year by MEC. The students are free to propose the title of the project based on the theme given.

2.2.3

7KHDVVHVVPHQWRIWKHSURMHFWLVFDUULHGRXWEDVHGRQVWXGHQWV¶UHSRUWRYHUDOOTXDOLW\RI project report and oral presentation. Students will be assessed by the same skill which is assessed in the practical work.

2.2.4

The report on project which has been done on third term should have the following format: (a) Title (b) Abstract (c) Introduction (d) Methodology (e) Observations, result and discussion (f) Conclusion (g) References/Bibliography

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The assessment framework of the project work is shown in the table below. Component Project report Project file Oral Presentation

Group

Individual

Total

66.67 %

±

66.67%

±

10%

10%

13.33%

10%

23.33%

Total

The written report should be at least 800 words and not more than 1500 words. The SURMHFWUHSRUWZLOOEHDVVHVVHGDVDJURXS¶VDVVHVVPHQWDQGVKRXOGEHDVVHVVHGEDVHGRQ the assessment criteria.

ST A l PM ex T C an he m is try

2.2.6

100%

2.2.7

The oral presentation will be assessed individually and as a group. On the individual level, each student is given a minimum of 5 minutes per student. For groups of three students, a maximum time limit of 20 minutes is allocated; whereas for groups of two students, the maximum limit is 15 minutes. The group presentation also includes those that do not exceed 5 minutes. Each presentation will have a Q & A session.

2.2.8

Students need to be aware that the written work they submit must be entirely their own and cite any source that had been referred to. Teachers should try to encourage students to take responsibility for their learning, so that they accept ownership of the work and take pride in it.

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2.3 Table of Summary of Experiments and Project

Experiment

Topic

Subtopic

Purpose

M ode of working

Report to be completed

First Term 1

Volumetric analysis

To determine the exact concentration of a monobasic acid, HX

Individually

In the laboratory

Acid base and redox

To determine the mass of sodium ethanedioate used to prepare a solution containing sodium ethanedioate and hydrated ethanedioic acid

Individually

In the laboratory

Purity and stoichiometry

To determine the purity of a sample of sodium sulphite

Individually

In the laboratory

Reaction kinetics

To determine the effect of temperature on the reaction rate

Individually

In the laboratory

Equilibrium and solubility

To determine the solubility product, Ksp, of MX2 and enthalpy change of solution, ǻH sol

Individually

In the laboratory

Thermochemistry

To determine the heat of reaction

Individually

In the laboratory

ElectrochemistryFaraday's Laws

To determine the percentage purity of copper metal by electrolysis

Individually

In the laboratory

ST A l PM ex T C an he m is try

2

Stoichiometry

3

4

Physical Quantity

5

Second Term 6 7

Physical Quantity

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Experiment

Topic

8

Technique

STPM 2014

Subtopic

Purpose

M ode of working

Report to be completed

To determine the cations and anions of inorganic substances

Individually

In the laboratory

9

Qualitative analysis

To determine the cations and anions in inorganic salts

Individually

In the laboratory

10

TechniqueSynthesis

To determine the percentage of aluminium in a sample X by means of the preparation of a complex compound of aluminium with 8-hydroxyquinoline

Individually/ Group

In the laboratory

Qualitative analysis

To study the reactions of alcohols and carbonyl compounds

Individually

In the laboratory

12

Qualitative analysis

To study the reactions of Individually organic nitrogen compounds (amides, amines and their salts, amino acids and proteins)

In the laboratory

13

TechniqueSynthesis

To prepare a sample of 2-(4-hydroxyphenylazo) benzoic acid

Group

At home

To enable students to acquire knowledge and skills in chemistry using ICT as well as to develop soft-skills

Group

At the end of third term

ST A l PM ex T C an he m is try

Qualitative analysis

Third Term 11

Project

Technique

Volumetric analysis/ Physical quantity/ Technique

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2.4 Experiment for First Term Experiment 1 Topic: Volumetric analysis

stoichiometry

Purpose: To determine the exact concentration of a monobasic acid, HX Question:

ST A l PM ex T C an he m is try

You are provided with a monobasic acid, HX, with a concentration in the range of 0.500 mol dm 3 to 1.00 mol dm 3. You are required to plan and carry out an experiment to determine the exact concentration of the HX solution provided.

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Experiment 2 Topic: Volumetric analysis Purpose:

Acid base and redox

To determine the mass of sodium ethanedioate used to prepare a solution containing sodium ethanedioate and hydrated ethanedioic acid

M aterials: KA 1 is a solution containing hydrated ethanedioic acid, H2C2O4.2H2O, and sodium ethanedioate.

ST A l PM ex T C an he m is try

KA 2 is a solution containing 3.50 g potassium manganate(VII) per dm3. KA 3 is a solution containing 1.70 g hydroxide ions per dm3. KA 4 is 1.00 mol dm-3 sulphuric acid.

Phenolphthalein is used as an indicator.

Procedure: (a)

Pipette 25.0 cm3 KA 1 into a titration flask. Add two or three drops of phenolphthalein and titrate this solution with KA 3. Record your readings in the table below. Repeat the titration at least two times to achieve accurate results.

Results: (b)

Record your titration readings in the table below.

Titration number

Rough

Accurate

First

Second

Third

Final reading/cm3

Initial reading/cm3

Volume of KA 3/cm3

(i) Calculate your average titre value showing the suitable titre values that you use.

(ii) 25.0 cm3 of KA 1 UHTXLUHG«««FP3 of KA 3 for a complete reaction.

(c)

Pipette 25.0 cm3 of KA 1 into a titration flask. Then add 25 cm3 of KA 4. Heat this solution to about 60 C, and titrate the solution with KA 2 until a faint pink colour persists in the solution. Repeat the titration at least two times to achieve accurate results.

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Results: (d)

Record your titration readings in the table below.

Titration number

Rough

Accurate First

Second

Third

Final reading/cm3 Initial reading/cm3 Volume of KA 2/cm3

ST A l PM ex T C an he m is try

(i) Calculate your average titre value showing the suitable titre values that you use.

(ii) 25.0 cm3 of KA 1 UHTXLUHG«««FP3 of KA 2 for a complete reaction.

Questions: (e)

Calculate the concentration, in mol dm 3, of hydrated ethanedioic acid in KA 1 solution.

(f)

Calculate the mass of ethanedioate ions, C2O42 , in 1.00 dm3 of KA 1.

(g)

Calculate the concentration, in mol dm 3, of ethanedioate ions which originated from the sodium ethanedioate salt.

(h)

Calculate the mass of sodium ethanedioate present in 1.00 dm3 of solution KA 1.

(i)

Calculate the percentage of sodium ethanedioate in solution KA 1.

(j)

Why was solution KA 4 added to solution KA 1 before the titration?

59

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Experiment 3 Topic: Volumetric analysis

Purity and stoichiometry

Purpose: To determine the purity of a sample of sodium sulphite M aterials: KA 1 is 0.050 mol dm 3 aqueous iodine. KA 2 is 0.100 mol dm 3 aqueous sodium thiosulphate. KA 3 is a solution containing 24.00 g of anhydrous sodium sulphite, Na2SO3, per dm3.

ST A l PM ex T C an he m is try

KA 4 is 2 g sodium hydrogencarbonate. Starch is used as an indicator.

I ntroduction:

The sulphite ion can be oxidised quantitatively to the sulphate ion by iodine in the presence of the hydrogen carbonate ion. SO32

SO42

+ I2 + H2O

2HI + 2HCO3

+ 2HI

2I + 2H2O + 2CO2

If a solution of sodium sulphite is added to an excess of a standard solution of iodine, the excess iodine in the resulting solution can be titrated with a standard solution of sodium thiosulphate. Hence the concentration of sodium sulphite can be determined. Procedure: (a)

Pipette 50.0 cm3 of KA 1 into a titration flask. Using another pipette, place 25.0 cm3 of KA 3 slowly into the titration flask containing KA 1 and shake. Add 2 g of KA 4 and shake the flask again. Titrate the resulting solution with KA 2 using starch as indicator. Repeat the titration as many times as you think necessary to achieve accurate results.

Results: (b)

Record your titration readings in the table below. Titration number

Rough

Accurate

First

3

Final reading/cm

Initial reading/cm3

Volume of KA 2/cm3

(i) Calculate your average titre value showing the suitable titre values that you used.

(ii) 50.0 cm3 of KA 1 UHTXLUHG«««FP3 of KA 2 for a complete reaction.

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Questions: (c)

Write a balanced equation for the reaction between iodine and the thiosulphate ion.

(d)

Calculate the volume of I2 that did not react with the sulphite ions.

(e)

Using your answer to (d), calculate the volume of I2 that reacted with the sulphite ions.

(f)

Using your answer to (e), (i) calculate the concentration, in mol dm 3, of the sulphite ions in solution KA 3, (ii) calculate the mass of Na2SO3 present in 250 cm3 of KA 3. Using your answer to (f)(ii), calculate the percentage purity of Na2SO3 that you used.

ST A l PM ex T C an he m is try

(g)

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Experiment 4 Topic: Reaction kinetics Purpose: To determine the effect of temperature on the reaction rate M aterials: KA 1 is 0.150 mol dm 3 potassium iodide solution. KA 2 is 0.5% starch solution. KA 3 is 0.050 mol dm 3 sodium thiosulphate solution.

ST A l PM ex T C an he m is try

KA 4 is 0.100 mol dm 3 hydrogen peroxide solution. KA 5 is 0.100 mol dm 3 sulphuric acid.

Procedure: (a)

Pipette 25.0 cm3 of KA 1 into a conical flask. By means of a measuring cylinder, add 10 cm3 of KA 2 and 25 cm3 of distilled water to the solution. Then run in 10.00 cm3 of KA 3 from the burette. Record the temperature of the mixture in the table below. Using a measuring cylinder, place 50 cm3 of KA 4 and 20 cm3 of KA 5 into a beaker. Transfer this mixture quickly into the conical flask above and immediately start the stopwatch. Swirl the conical flask regularly and record the time when the mixture turns blue. Note the time taken to the nearest second. If no colour appears after two minutes, repeat the procedure. Repeat the experiment at the following temperatures: (i) 10 C below room temperature;

(ii) 10 C above the room temperature and;

(iii) 20 C above the room temperature.

Results: (b)

Record and complete your readings in the table below. Mixture

1

2

3

4

3

25.0

25.0

25.0

25.0

3

Volume of KA 2/cm

10

10

10

10

Volume of distilled water/cm3

25

25

25

25

Volume of KA 1/cm

Volume of KA 3/cm3

10.00

10.00

10.00

10.00

3

50

50

50

50

3

20

20

20

20

Volume of KA 4/cm Volume of KA 5/cm Temperature, T/ C Time, t/s

1 /s t

1

62

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Questions: (c)

Why does the mixture in (a) turn blue?

(d)

Plot a graph of

(e)

From your graph, what could be the effect of temperature on the reaction rate?

(f)

Using your graph,

1 t

against T.

(i) compare the rate of reaction at 30 C with the rate of reaction at 40 C,

ST A l PM ex T C an he m is try

(ii) give an explanation for your answer.

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Experiment 5 Topic: Equilibrium and solubility Purpose:

To determine the solubility product, Ksp, of MX2 and enthalpy change of solution,

ǻH sol M aterials: KA 1 is 0.100 mol dm±3 of M 2+ ion.

ST A l PM ex T C an he m is try

KA 2 is 0.500 mol dm±3 of X ion. I ntroduction:

A compound MX2, which is slightly soluble in water, is formed when two solutions, one containing M 2+ ions and the other X ions, are mixed together. The compound will be 2

precipitated at the temperature of reaction when the value of the product M 2+ X is greater than the value of the solubility product, Ksp, of the compound and a saturated solution is formed. The chemical equilibrium of the compound in the saturated solution is represented by

M 2+ (aq) + 2 X (aq)

MX2(s)

Procedure: (a)

Transfer 12.00 cm3 of KA 1 from a burette into a boiling tube. Place thermometer in the boiling tube and titrate solution KA 1 with KA 2 from a second burette until the first appearance of the white precipitate. Record the temperature of the first appearance of the white precipitate and the volume of KA 2 used in the table below.

(b)

Transfer 12.00 cm3 of KA 1 from a burette into a boiling tube. Place a thermometer in the boiling tube and from the second burette run 7.00 cm3 of KA 2 into it. Stir the saturated solution gently with the thermometer. Leave the boiling tube for a few minutes until the reaction has reached equilibrium.

Then place the boiling tube in a hot water bath at 75 °C ± 80 °C. Stir the saturated solution until all the precipitate has dissolved. Do not remove the thermometer from the solution. Remove the boiling tube from the hot water bath and continue to stir the solution gently with the thermometer until the first appearance of white precipitate is observed. Record the temperature of the first appearance of the white precipitate in the table below. Wash and clean the thermometer for the next experiment. Repeat the experiment with different volumes of KA 2 as shown in the table below.

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Results: Record and complete your readings in the table below. Experiment number

Volume of KA 1/cm3

Volume of KA 2/cm3

1

12.00

2

12.00

7.00

3

12.00

9.00

4

12.00

11.00

Temperature of the first appearance of precipitate/°C

Solubility product, Ksp

ST A l PM ex T C an he m is try

(c)

5

12.00

13.00

Questions: (d)

Calculate the solubility product, Ksp, of compound MX2 at each temperature recorded. Record your results in the table above.

(e)

Plot a graph of solubility product, Ksp, of compound MX2 against temperature.

(f)

Use your graph to determine the solubility product of compound MX2 at 50 °C.

(g)

The relationship between solubility product, Ksp, of a compound and temperature, T, in Kelvin is given by the equation

log10 K sp

H

1

2.303R T

constant

(i) From the results obtained in (d), calculate the enthalpy change of solution, ǻH sol for the reaction

M 2+ (aq) + 2 X (aq)

MX2 (s)

(ii) Is the reaction exothermic or endothermic? Explain your answer.

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2.5 Experiment for Second Term Experiment 6 Topic: Thermochemistry Purpose: To determine the heat of reaction M aterials: KA 1 is 2.00 mol dm 3 hydrochloric acid. KA 2 is solid anhydrous sodium carbonate.

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KA 3 is solid sodium hydrogencarbonate.

Procedure: (a)

Using a burette, run 30.00 cm3 of KA 1 into a plastic cup. Leave the cup with its contents to stand for a few minutes, then record the temperature of the solution in the table below.

Weigh a stoppered test-tube containing KA 2 and record its weight in the table below. At one go, transfer all of the KA 2 into the plastic cup containing KA 1. Ensure that all solid leaving the test-tube enters the plastic cup and no liquid is lost through splashing. Stir the solution carefully with the thermometer, and record the highest temperature attained. Reweigh the empty test-tube and record its weight in the table below. Repeat the above procedure using KA 3 to replace KA 2.

Results: (b)

Record all your readings and weights in the table below.

KA 2

KA 3

Weight of test-tube + solid/g Weight of empty test-tube/g Weight of solid/g

Final temperature of mixture/ C Initial temperature of acid/ C Temperature change/ C

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Questions: (c)

Assuming that the heat loss to the plastic cup, thermometer and surroundings can be ignored and the specific heat capacity and density of all the solutions are 4.2 J g 1 K 1 and 1.0 g cm 3 respectively, calculate (i) the heat change in the reactions involving KA 1 with KA 2 and KA 1 with KA 3, (ii) the number of moles of anhydrous sodium hydrogencarbonate in KA 2 and KA 3 respectively,

carbonate

and

sodium

(iii) the enthalpy change for the reactions of KA 2 and KA 3 with hydrochloric acid respectively. Write balanced equations for the reactions of KA 2 and KA 3 with hydrochloric acid.

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(d) (e)

Draw an energy level diagram for the related reactions.

(f)

Calculate H for the conversion reaction of sodium hydrogencarbonate to sodium carbonate using Hess Law and (e).

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Experiment 7 Topic: Electrochemistry

FDUDGD\¶V/DZV

Purpose: To determine the percentage purity of copper metal by electrolysis Question:

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You are required to plan and to carry out an experiment to determine the percentage purity of copper metal by electrolysis.

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Experiment 8 Topic: Qualitative analysis Purpose: To determine the cations and anions of inorganic substances Procedure: (a)

Solids KA 1 and KA 2 are simple salts. Carry out the following experiments with (i) solid KA 1 to identify its cation and anion, (ii) solid KA 2 to identify its cations.

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In all the experiments, the reagent should be added gradually until no further change is observed. Record your observations and the deductions you make from them in the spaces provided. Deduce what you can about KA 1 and KA 2. Observations should include details of colour changes, precipitates and tests on gases evolved, and you should indicate clearly at which stage in the test a change occurs.

Tests on KA 1

Test

Observation

Deduction

(b) Add dilute hydrochloric acid to a small amount of solid KA 1, then warm gently.

(c) Dissolve solid KA 1 in distilled water and filter. Use separate portions of the filtrate for tests (i) to (vi).

(i) Add aqueous sodium hydroxide, then in excess.

(ii) Add aqueous ammonia, then in excess followed by aqueous ammonium chloride.

(iii) Add aqueous iron(III) chloride, then warm.

(iv) Add aqueous silver nitrate followed by dilute nitricacid. (v) Add aqueous disodium hydrogen phosphate.

(vi) Add aqueous potassium chromate(VI) followed by dilute hydrochloric acid.

Identity of KA 1:««««««««««««««««««««««................................. 69

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Tests on KA 2 Test

Observation

Deduction

(d) Dissolve all of solid KA 2 in distilled water and filter. Use separate portions of the filtrate for tests (i) to (v). (i) Add aqueous sodium hydroxide, then in excess, and warm.

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(ii) Add aqueous potassium iodide.

(iii) Add aqueous potassium chromate(VI). (iv) Add aqueous sodium ethanoate, then warm.

(v) Add aqueous sodium carbonate, then warm.

Identity of cations present in KA 2««««««««««««««««««««««««

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Experiment 9 Topic: Qualitative analysis Purpose: To determine the anions in inorganic salts Procedure: (a)

You are required to plan and carry out tests to identify the anions in a solid mixture KA 1.

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In all the tests, the reagent should be added gradually until no further change is observed. Record your observations and the deductions you make from them in the spaces provided. Deduce what you can about the anions in KA 1. Observations should include details of colour changes, precipitates and tests on gases evolved, and you should indicate clearly at which stage in a test a change occurs.

Tests on KA 1

Test

Observation

71

Deduction

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STPM 2014 Observation

Deduction

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Test

Identity of anions present in KA 1««««««««««««««««««««««« 72

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Experiment 10 Topic: Technique Purpose:

Synthesis

To determine the percentage of aluminium in a sample X by means of the preparation of a complex compound of aluminium with 8-hydroxyquinoline

M aterials: KA 1 is a solution of 8-hydroxyquinoline in ethanoic acid. KA 2 is 2 mol dm 3 aqueous ammonium ethanoate.

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KA 3 is sample X. KA 4 is 2 mol dm 3 hydrochloric acid.

I ntroduction:

Aluminium in a certain sample can be determined quantitatively by means of the process of formation of complex compounds, for example, an alum complex is produced by the reaction of an alum with 8-hydroxyquinoline.

Al3+ + 3

+ 3H+

Procedure: (a)

Weigh out accurately between 0.25 g and 0.30 g of KA 3. Record your readings in the table below. Mass of container + KA 3/g Mass of empty container/g Mass of KA 3/g

Place all of KA 3 into a 250 cm3 beaker, and add 150 cm3 of distilled water followed by one drop of KA 4. Warm the mixture to a temperature between 60 C and 70 C. Then add 25 cm3 of solution KA 1, followed slowly by 50 cm3 of solution KA 2. A precipitate will be formed. Remove the beaker. Stir this solution for half an hour using a magnetic stirrer.

Weigh an empty crucible and record your readings in the table on the next page. Filter the solution above and wash the precipitate with cold distilled water. Transfer the precipitate into an empty crucible and dry the precipitate in the oven at about 120 C. Cool and weigh the crucible together with its contents.

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Results: (b)

Record your readings in the table below. Mass of crucible + precipitate/g Mass of empty crucible/g Mass of precipitate/g

Questions: Explain

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(c)

(i) why the mixture of solutions KA 1 and KA 2 needs to be stirred for half an hour using the magnetic stirrer,

(ii) why the complex precipitate is washed with cold water.

(d)

How would you ensure that the complex precipitate obtained is completely dried?

(e)

Calculate the mass of 1 mole of complex compound with the formula Al(C9H6NO)3 .

(f)

Calculate the percentage of aluminium in the complex compound.

(g)

Calculate the percentage of aluminium in sample X.

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2.6 Experiment for Third Term Experiment 11 Topic: Qualitative analysis Purpose: To study the reactions of alcohols and carbonyl compounds Procedure: (a)

KA 1 is an alcohol and KA 2 is a carbonyl compound. Carry out the following tests to confirm the functional groups/structures present in these two compounds.

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In all the tests, the reagents should be added gradually until no further change is observed. Record your observations and deductions you make from them in the spaces provided. Observations should include details of colour changes and precipitates formed.

Tests on KA 1

Test

Observation

Deduction

(b) Add 1 cm3 of glacial ethanoic acid to 1 cm3 KA 1 followed by 3 drops of concentrated sulphuric acid, then warm gently in a hot water bath. Cool and pour the resulting mixture into a beaker containing distilled water. (c) Add 1 2 drops of acidified potassium manganate(VII) solution to 2 cm3 of KA 1 and heat gently.

(d) Place about 5 drops of KA 1 in a test tube and add 2 cm3 of distilled water. Shake the test tube until all the samples have dissolved. Add 1 cm3 of 2.5 mol dm±3 sodium hydroxide solution, and then slowly add the iodine potassium iodide solution, with shaking until the dark colour of iodine persists. Continue adding the iodine potassium iodide solution until the iodine colour is not discharged for 2 minutes at 60 °C.

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Tests on KA 2 Test

Observation

Deduction

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(e) Dissolve about 0.5 cm3 or 50 mg of KA 2 in 2 cm3 95% ethanol. Add 2 to 3 drops of this mixture into the test tube containing 3 cm3 of 2, 4-dinitrophenylhydrazine reagent. Shake the test tube and observe the formation of any precipitate. If no precipitate forms, immediately allow the mixture to stand for 5 10 minutes.

(f) Dissolve about 1 cm3 or 0.2 g of KA 2 in 5 cm3 distilled water and add 5 cm3 )HKOLQJ¶VVROXWLRQ6ORZO\, shake the test tube and heat the mixture to boiling. Cool the mixture to room temperature. (g) Add 2 3 drops or 0.1 g of KA 2 to be WHVWHGWRWKHIUHVKO\SUHSDUHG7ROOHQV¶ reagent. Shake the test tube slowly and note the formation of silver mirror or precipitate. If there is no precipitate after 10 minutes, warm the mixture in a water bath at 30 °C for 5 to 10 minutes. (h) Add 1 2 drops of acidified potassium manganate(VII) solution to 2 cm3 of KA 2 and heat gently.

(i) Place about 5 drops of KA 2 in a test tube and add 2 cm3 of distilled water. Shake the test tube until the samples have dissolved. Add 1 cm3 of 2.5 mol dm±3 sodium hydroxide solution, and then slowly add the iodine potassium iodide solution, with shaking until the dark colour of iodine persists. Continue adding the iodine potassium iodide solution until the iodine colour is not discharged for 2 minutes at 60 °C.

Remove the excess iodine by adding a few drops of 2.5 mol dm±3 sodium hydroxide solution, with shaking. Add equal amount of water and allow the mixture to stand at room temperature for 15 minutes.

Identity of functional group/structure in KA 2«««««««««««««««««««

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Experiment 12 Topic: Qualitative analysis Purpose:

To study the reactions of organic nitrogen compounds (amides and amines)

Procedure: (a)

KA 1 and KA 2 are organic nitrogen compounds. Carry out the following tests to identify KA 1 and KA 2.

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In all the tests, the reagents should be added gradually until no further change is observed. Record your observations and deductions you make from them in the spaces provided. Comment on the types of chemical reaction occurring and deduce the functional groups present in these compounds. Observations should include details of colour changes, precipitates, and tests on gases evolved, and you should indicate clearly at which stage in the test a change occurs.

Tests on KA 1

Test

Observation

Deduction

(b) (i) Add 2 cm3 of distilled water to about 0.1 g of KA 1 in a test tube and shake vigorously. (ii) Then add 2 or 3 drops of Universal indicator.

(c) To about 0.1 g of KA 1 in a test tube, add 3 cm3 of 5% solution of sodium hydrogen carbonate and shake.

(d) Add 0.5 cm3 or 0.5 g of KA 1 to 1.5 cm3 of 4.5 mol dm±3 hydrochloric acid and cool the solution to 0 °C. Dissolve 0.5 g of sodium nitrite in 2.5 cm3 distilled water and add this solution drop wise, with shaking, to the cold solution. Then, transfer 2 cm3 of the solution to a clean test tube, warm gently, and identify for the gas evolved. (e) Add about 1 cm3 dilute sulphuric acid to about 0.2 g of KA 1 in a test tube. Shake and heat the mixture in a hot water bath for 5 minutes. Cautiously smell the vapour evolved/released.

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Test

Observation

Deduction

««««««««

««««««««

(f) (i) Add 1 cm3 of sodium hydroxide solution to 0.4 g of KA 1 in a test tube. Shake and heat the mixture in a hot water bath for 5 minutes. (ii) Acidify the mixture produced in (i) and heat the mixture in the hot water bath for 5 minutes.

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Cautiously smell the vapour evolved/released.

Identity of KA 1: .............................................................................................................................

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Tests on KA 2 Test

Observation

Deduction

(h) To about 2 drops of KA 2 in a test tube, add 2 cm3 of distilled water and shake vigorously. Then, add 2 or 3 drops of Universal indicator.

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(i) To about 10 drops of KA 2 in a test tube, add dilute hydrochloric acid and shake until dissolved. Then, add 2 cm3 of 0.5 mol dm±3 sodium hydroxide, shake and warm gently in a hot water bath.

(j) Add 0.5 cm3 or 0.5 g of KA 2 to 1.5 cm3 of 4.5 mol dm±3 hydrochloric acid and cool the solution to 0 °C. Dissolve 0.5 g of sodium nitrite in 2.5 cm3 distilled water and add this solution drop wise, with shaking, to the cold solution. Then, transfer 2 cm3 of the solution to a clean test tube, warm gently, and identify for the gas evolved. (k) To about 10 drops of KA 2 in a test tube, add dilute hydrochloric acid and shake until dissolved. Then, add bromine water drop by drop. Shake gently.

If KA 2 has the relative molecular mass of 73.0, the identity of KA 2: ......................................

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Experiment 13 Topic: Technique-Synthesis Purpose: To prepare a sample of 2-(4-hydroxyphenylazo)benzoic acid M aterials: KA 1 is solid 2-aminobenzoic acid. KA 2 is 1.70 mol dm 3 hydrochloric acid. KA 3 is solid sodium nitrite.

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KA 4 is a mixture of 0.30 mol dm 3 phenol and 1.35 mol dm 3 sodium hydroxide. KA 5 is 4.00 mol dm 3 hydrochloric acid.

I ntroduction:

Azo dyes are easily prepared by the coupling of diazotised aniline with either a phenol or aniline. In this experiment, 2-aminobenzoic acid is diazotised and coupled with phenol in an alkaline solution to give the salt of an azo dye. Acid is added to produce the azo dye of 2-(4-hydroxyphenylazo)benzoic acid. COOH

COOH

N2Cl

NH2

HNO2, HCl