Paper 3 Chemistry Form 4 Final Exam

CONFIDENTIAL Chemistry 4541/3 October 2014 1 Hour 30 minutes

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I/C No.

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Class.

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FINAL EXAMINATION

SECONDARY 4

CHEMISTRY Paper 3 1 HOUR 30 MINUTES

DO NOT OPEN THIS BOOKLET UNTIL INSTRUCTED 1. This question paper consists of two questions:

Question

Question 1 and Question 2. 2. Answer all the questions. You may use

equations, diagrams, tables, graph, and other suitable method to explain your answer.

Full Mark marks obtained

1

33

2

17

Total

50

3. The diagrams in the questions are not drawn

to scale unless stated. 4. The marks allocated for each question or subpart of a question is shown in brackets. 5. You may use a non-programmable scientific calculator. 6. You are advised to spend 45 minutes to answer Question 1 and 45 minutes for

Question 2.

Prepared by Checked by Approved by

: Mrs. Wan Nurul Aini Wan Nor Yuhaidi : Mr. Tan K. K. : Mrs. Hariah Muhi This question paper consists of 6 printed pages

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4541/3 Answer all questions.

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Diagram 1.1 shows the apparatus set – up for an experiment to construct the electrochemical series based on the potential difference between pairs of metals in a simple voltaic cell. Copper plate is paired with zinc, lead, iron, aluminium and magnesium metals in Cell I, Cell II, Cell III, Cell IV and Cell V respectively. In each cell, copper acts as the positive terminal.

Diagram 1.1 Diagram 1.2 shows the voltmeter readings of each cell.

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Cell I: Cu – Zn

Cell II: Cu – Pb

Voltmeter reading: ____________V

Voltmeter reading: ____________V

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Cell III: Cu – Fe

Cell IV: Cu – Al

Voltmeter reading: ____________V

Voltmeter reading: ____________V

Cell V: Cu - Mg

Voltmeter reading: ______________V Diagram 1.2 (a)

Record the voltmeter readings of each cell in the spaces provided in Diagram 1.2. [3 marks]

(b)

Complete the table to record the cell voltage and negative terminal in each of these cells.

Cell I II III IV V

Pair of metals Zink – Copper Lead – Copper Iron – Copper Aluminium – Copper Magnesium - Copper

Negative terminal

Cell voltage/V

[3 marks]

(c) 4541/3

State three observations and the corresponding inferences in Table 1.1. The [Please turn over CONFIDENTIAL

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observations should not include the deflection of voltmeter needle. Observation

Inference

Negative terminal

Positive terminal

Colour of the solution

[6 marks] (d) State one hypothesis for this experiment. ……………………………………………………………………………………… ………………………………………………………………………………………... [3 marks] (e)

For this experiment, state the: (i) manipulated variable : ……………………………………………………... (ii) responding variable : ……………………………………………………... (iii) constant variable : ……………………………………………………... [3 marks]

(f)

State the operational definition for the position of metals in the electrochemical series. ……………………………………………………………………………………… ………………………………………………………………………………………... [3 marks] (g) Arrange the six metals in descending order of electropositivity. ……………………………………………………………………………………… [3 marks] 4541/3

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(i) The experiment is repeated using another copper plate to pair with the copper plate. Predict the voltmeter reading.

………………………………………………………………………………….. [3 marks] (ii) Explain the answer in 1(h)(i). ………………………………………………………………………………… ………………………………………………………………………………….. [3 marks] (i) Classify the ions present in the electrolyte of copper (II) sulphate in this experiment by completing Table 1.2. Anions

Cations

(i)

(iii)

(ii)

(iv) [3 marks]

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Diagram 2 shows the apparatus set – up for titration of 25.0 cm3 of 1.0 mol dm-3 of potassium hydroxide, KOH solution with dilute hydrochloric acid, HCl. Phenolphthalein is used as an indicator.

Dilute hydrochloric acid

Potassium hydroxide + phenolphthalein Diagram 2 Based on this situation, plan one experiment in the laboratory to determine the concentration of hydrochloric acid by finding the end point of titration. Your planning should include the following aspects. (a) (b) (c) (d) (e) (f)

Aim of the experiment Statement of the hypothesis All the variables List of substances and apparatus Procedure of the experiment Tabulation of data [17 marks]

END OF QUESTION PAPER

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ANSWER SCHEME CHEMISTRY FINAL EXAMINATION SECONDARY 4 (PAPER 3)

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