checklist for scoring A+ in chemistry

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 QUESTION 1.State the kinetic theory of matter State one example to support the kinetic theory of matter

2.What are atom,molecule,and ion

3.What is melting point?

4.Define proton number and nucleon number

5.State the meaning of isotopes

6.State the uses of isotopes such as carbon-14 and cobalt-60 7.Explain why the temperature remains unchanged during the melting process 8.Explain why the temperature remains unchanged during the freezing point 9.A solid compound is heated until it converts into gas.Explain the changes in energy content,forces of attraction between the particles and arrangement of particles

ANSWER -Matter consist of molecules. These are the smallest particles, which are capable of free existence and retain all the chemical properties of the parent substance. -The molecules are always in a state of random continuous motion. -The molecules exert forces on one another. These forces depend upon intermolecular distance. Gas. Atom-smallest particle that can participate in chemical reaction Molecule-Group of 2 or more atoms which are chemically bonded together Ion-Charged particle Melting Point-The temperature that remains constant at which a solid changes into a liquid at aparicular pressure Proton Number-The number of proton presence in an atom Nucleon Number-The total number of proton and neutron in an atom -Atoms of the same element with the same number of proton but different number of neutrons Cobalt-60:Radiotheraphy of treating cancer Carbon-14:Carbon dating(estimate age of fossils and artefacts) -This is because the heat energy absorbed by the particles is used to overcome the forces of attraction between the particles -This is because the heat loss to the surrounding is balanced to the heat energy liberatedas the particle attracts one another to form solid -When a solid is heated,the particles in the solid absorb heat energy and vibrate stronger at its fixed position due to the increase in kinetic energy of the particles .When the particles managed to overcome the strong force of attraction between them they will finally changed into liquid.In liquid form,the particles have a higher amount of kinetic energy than it is in solid and they can move in a

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 more random manner.When it reaches the boiling point,the particles can move freely and in a random manner as it has changed its state into gas which has the highest kinetic energy and the weakest force of attraction between particles SOLID -Low Kinetic Energy

-High Force of Attraction Between Particles

10.State the main subatomic particles of an atom. Compare and contrast the relative atomic mass and the relative charge of the subatomic particles of the atom

11. is the symbol of aluminium a)Determine the number of neutron of aluminium b)Draw the electron arrangement of aluminium

-Particles are Arranged in orderly manner -Rotate and vibrate at fixed position only Subatomic Particles Proton Neutron Electron

LIQUID -Kinetic Energy is lower than it is in solid and higher than gas -Force of attraction between paricles are as strong as it is in solid -Particles are closely packed together but can move in a random manner

GAS -Low kinetic Energy

Relative Atomic Mass 1 1 0.0005

Relative Charge +1 0 -1

a)Neutron number=14 b)

-Low Force of attraction between particles

-Particles can move freely and randomly

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

12.Solid Z has a melting point of 65C.Describe a laboratory experiment to determine the melting point of Z.Your answer should show how the melting point of Z is determined

13.Compound W has a freezing point of 82C.Describe a laboratory experiment to determine the freezing point of W

1.A boiling tube is filled with solid Z to a depth of 3cm and thermometer is put into it 2.The boiling tube is suspended in a beaker half filled with water using a retort stand and clamp.The level of solid Z in the boiling tube must be below the level of water in the beaker. 3.The water is heated and the solid Z is stirred slowly with the thermometer.When the temperature of the solid Z reaches 450C,the stopwatch is started. 4.The temperature and the state of substance Z is recorded at half minute intervals until the temperature of substance Z reaches 800C. 1.Step 1 to 2 of the above experiment is repeated using compound W instead. 2.The water is heated and the compound W is stirred slowly with the thermometer.When compound W reaches 950C,the heating is stopped 3.The boiling tube is removed from the water bath and the outer surface is dried up.Then it is immediately put into a conical flask with half of the top of the boiling tube clamped using a retort stand.The compound W is stirred continuosly. 4.The temperature and the state of compound W is recorded at half-minute intervals until the temperature drops to about 750C.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 QUESTION 1.State the meaning of relative atomic mass based in carbon-12 scale 2. Define a mole

3.State the meaning of molar mass 4.State the meaning of molar volume of gas 5.State the meaning of empirical formula

6.State the meaning of molecular formula

7.Explain why we couldn’t determine the empirical formula of copper()oxide by heating copper powder in a crucible

8.Compare and contrast empirical formula with molecular formula using ethane as an example

9.Vinegar is a dilute ethanoic acid with a molecular formula CH3COOH. a)Find the empirical formula of ethanoic acid b)Find the percentage composition by mass of carbon in ethanoic acid 10.3.6 of carbon reacted with 0.8g of hydrogen to form a compound a)Determine the empirical formula of the compound formed b)Given thet the relative molecular mass of the compound is 88g,find its molecular formula.[Relative atomic mass:Cu,12;H,1]

ANSWER -Number of times the mass of an atom is greater than a/12 times of the mass of a carbon-12 atom. The relative mass of carbon-12 atom is 12.000. -An amount of substance that contains as many particles as the number of atom in exaclt 12g of carbon-12 -Mass of 1mol of substance of units,molecules or atoms. -The volume occupied by one mole of gas. -The formula that shows the simplest whole number ratio of atoms of each element in the compound. -The formula that shows the actual number of atoms of each element that is present in a molecule of the compound -Molecular formula=(empirical formula)n -This is because copper is not a reactive metal so it will take a long time for It to react with the oxygen in air.Thus,to determine the empirical formula of copper()oxide,another method is used.The method uses continuous flowing hydrogen gas to obtain copper metal from the reduction of copper()oxide. Ethane Empirical Formula Molecular Formula CH3 C2H6 a)Empirical Formula:CH2O b)Percentage of carbon in ethanoic acid=2(12) 100%=40% 2(12)+4(1)+2(16) a) Carbon 3.6 3.6÷12=0.3

Hydrogen 0.8 0.8÷1=0.8

Mass(g) No.of Moles(mol) Ratio of 3 8 moles Thus,the empirical formula of the compound is C3H8

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 b)(C3H8)n=88 (3(12)+8(1))n=88 n=

11.Hydrogen gas is reacted with 20g of hot copper()oxide powders to produce solid copper and water a)Write the chemical equation for the reaction b)Calculate the maximum mass of solid copper formed[Relative atomic mass:Cu,64;O,16;H,1]

12.Describe a laboratory experiment to determine the empirical formula of magnesium oxide and copper()oxide Your answer should include all the precautions and calculations involved’[Relative atomic mass:Mg,24;O,16;Cu,64;H,1]

=2

Thus,the molecular formula of the compound is C6H16 a)Cuo+H2→Cu+H2O b)No.of moles of CuO=20g+(64+16)gmol-1 =0.25mol Ratio of moles CuO:Cu=1:1 So Cu has 0.25mol. Mass of Cu=0.25mol x 64gmol-1 =16g Title

Empirical formula of copper(II) oxide

Aim

To determine the empirical formula of copper(II) oxide

Problem How does the formula of Statement copper(II) oxide determine? Hypothesis The empirical formula of copper(II) oxide can be determined by finding out the mass of copper and oxygen in a sample of copper(II) oxide

Apparatus U tube Stoppers Glass tube Combustion tube with a small hole at the end Retort stand and clamp Spatula Porcelain dish

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 Bunsen burner Balance Preparation for hydrogen gas Thistle funnel Flat-bottomed flask Material Hydrogen gas, H2 Copper(II) oxide Anhydrous calcium chloride, CaCl2 Wooden splinter Preparation for the hydrogen gas Dilute hydrochloric acid Zinc pieces Variables Manipulated variable: Mass of copper oxide Responding variable: Mass of copper formed Controlled / Fixed variable: An excess of hydrogen gas

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

1.State the basic principle of arranging the elements in the Periodic Table from its proton number 2.State the physical properties of Group 1

3.State the physical properties of Group 17

4.State the changes in the atomic size and the electronegativity of elements across Period 3

Increasing the proton number

-Atomic size increases-When going down the group,the number of shells occupied with electrons increases -Density increases-The increase in atomic mass is bigger than the increase in atomic radius. -Melting and boiling point increase-The metallic bond between the atoms becomes weaker down the group as the atomic radius increase.Thus less heat energy is required to overcome the weaker forces of attraction between the atoms during melting/boiling -Electropositivity of the metals increases-As atomic radius becomes larger down the group the force of attraction between the nucleus and the single valence electron becomes weaker.Hence,the elements lose the single valence electron more easily down the group. -Reactivity Increase-Reactivity increases because the atomic size increase,the valence electron in the outermost shell becomes further away from the nucleus.Hence,the atoms can easily donate the single valence electron to achieve the stable electron arrangement of the atom of noble gas. -Reactivity Decrease-This is because the atomic size of halogen increases.Thus the outermost occupied shell of each halogen atombecomes further from nucleus.Thus,the strength to attract one electron into th valence shell by the nucleus become weaker. Atomic size decreases from left to right -The proton number increases from left to right -The nuclei charge,positive charge in the nucleus increases -Nuclei attraction force between the nucleus and the valence electron increase -Valence electron becomes closer to the nucleu -Thus,atomic size becomes smaller

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 When across period 3 from sodium to argon,the electronegativity increases

5.State three special properties of transition elements

-The elements from group 3 to group 12 in the periodic table -Has high melting and boiling point -has high tensile strength

6.State the position of element Table.Explain your answer

-Element X has an electron arrangement of 2.8.8.2.Hence,it is positioned at period 4 group 2.(Period=no of shells;Group=valence number) -This is because the number of proton increases from left to right.This causes the positive charge in the nucleus to increase.The nuclei attraction force between the nucleus and the valence electron increase.The valence shell containing valence electron becomes closer to the nucleus.Hence,the atomic size decreases from sodium to argon. -This is because the number of proton increases from left to right.This causes the positive charge in the nucleus to increase.The increase of proton causes valence shell containing valence electron to be closer to the nucleus.The more the proton number,the stronger the force to attract valence electron and electrons into the valence shell.Hence,the electronegativity increases across period 3

in Periodic

7.When across Period 3 from sodium to argon,the atomic size decreases.Explain why.

8.When across Period 3 from sodium to argon,the electronegativity increases.Explain why.

9.The reactivity of group 1 increases when going down the group.Explain why.

10.The reactivity of group 17 decreases when going down the group.Explain why.

-Reactivity increases because the atomic size increase,the valence electron in the outermost shell becomes further away from the nucleus.Hence,attraction between nucleus and valence electron becomes weaker.Thus,the atoms can easily donate the single valence electron to achieve the stable electron arrangement of the atom of noble gas -This is because the atomic size of halogen increases.Thus,the outermost occupied shell of each halogen atom becomes further from nucleus.Thus,the strength to attract one electron into the valence shell by the nucleus becomes weaker.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 11.Why helium gas in not reactive?

12.X in an element from Group 1.X burnt in oxygen and the products is dissolved in water.What is the property of the solution formed?Explain why. 13.Chlorine gas is dissolved in water.What can you observe is a piece of blue litmus paper is immersed into the solution formed?Explain why.

14.W is an element from Group 1.Predict the chemical reaction of W with: a)water b)oxygen State the observation and write the chemical equation involve.

-This is because it is a noble gas which has octect electron arrangement.Thus,it does not need to receive or losses any electron making it not reactive. -The solution form is an alkaline solution.It reacts with acid to form salt and water.The solution formed has this characteristic because group 1 elements are alkali metals whereby its oxide can dissolve in water to form alkali(XOH). -Chlorine water changes the blue litmus paper into red then white.This happens because chlorine gas is an acidic gas and when it dissolves in water,its acidic properties are displayed and it becomes hydrochloric acid.The litmus paper hten changes into white as the solution has bleaching properties(HOCl) Cl2+H2O HCl+HOCl Reaction With Water

Oxygen

Observation It reacts quickly with water.The solution formed changes the red litmus paper into blue It bums brightly with flame.White solid is produced and it dissolves in water.The solution formed changes red litmus paper blue

Equation 2W + 2H2O 2WOH + H2

4W+O2 2W2O W2O+H2O 2WOH

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 15.Describe a laboratory experiment to compare the reactivity of elements in Group 1:lithium,sodium and potassium. 16.Describe a laboratory experiment to compare the reactivity of chlorine,bromine and iodine in the reaction with iron wool.State the observation and write the chemical equations involve in reactions.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

1.What is anion? 2.What is cation? 3.State two physical properties of ionic compounds 4.State two physical properties of covalent compounds 5.Explain why sodium chloride can conduct electricity in aqueous state but cannot conduct electricity in solid state.

6.Magnesium chloride and hydrogen chloride are two compounds of chlorine.At room condition,magnesium chloride exists as a solid but hydrogen chloride exists as gas.Explain why.

-A negatively charged ion -A positively charged ion

-This is because in aqueous state the ions that made up sodium chloride are able to move freely in the solution.This means that there are charges moving in the solution.Hence,it can conduct electricity.However,in solid state,the ions are at fixed position in lattice.They are unable to move around freely.Thus,it cannot conduct electricity. Magnesium chloride Solid

Ionic compound High Ionic compound is held together by a strong bond called ionic bond.This means that more heat energy is needed to break the bonds and change the state of the compound.Hence,at a moderate room temperature it is in solid state

Aspects of view State at room temperatue Type of compound Boiling point Inference

Hydrogen chloride Gas

Covalent comppund Low Covalent compound is held together by weak intermolecular forces(Vander-Waals force).This means that a small amount of heat energy is sufficient to change its state.Hence at a moderate room temperature it is in gas state

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

7.Describe the formation of ionic bond in sodium chloride,NaCl.

8.By using example,describe the formation of covalent bond between element from Group 14 and element from Group 17.

9.Draw electron arrangement of the compound formed from the following elements. a)Nitrogen and hydrogen

-A sodium atom has 11 electrons and it has an electron arrangement of 2.8.1.This electron arrangement is not stable.It needs to donate an electron to achieve an octet electron arrangement.When a sodium atom donates an electron,it will become sodium ion with the electron arrangement of 2.8. -Chlorine atom has 17 electros and it has an electron arrangement of 2.8.7.This configuration is unstable.It needs to receive one electron to become stable and achieve an octet electron arrangement.When a chlorine atom receive electron,it will become chloride ion with the electron arrangement 2.8.8. -When a sodium atoms reacts with a chlorine atom,an electron of the sodium atom is given to the chlorine atom.The positively charged ion Na+ will attract to the negatively charged ion,Cl- to form an ionic compound,sodium chloride, NaCl.This force enables the two ions to stick together through ionic bond. -Example of formation:tetrachloromethane,CCl4 (Carbon-G14;Chlorine-G17) -The formula of tetrachloromethane molecule is CCL4.Carbon is in group 14 of the periodic table.It has four electron in its valence shell.In order to achieve the octet electron arrangement,each carbon atom needs another four more electrons to form an octet electron arrangement. -Chlorine atom is in group 17 of the periodic table.It has 7 valence electron.It needs one more electron to achieve the octet electron arrangement. -When one carbon atom share one electron with four chlorine atom,both carbon atom and chlorine atom can achieve a stable electron arrangement.This means that each chlorine atom share pair of electron with a carbon atom.This indicates single covalent bond.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 b)Carbon and oxygen c)Magnesium and chlorine d)Carbon and hydrogen e)Hydrogen and chlorine f)Sodium and oxygen

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 1.State the meaning of electrolyte

2.State the meaning of electrolysis

3.State three factors affecting electrolysis of an aqueous solution

4.explain why solution of hydrogen chloride in water can conduct electricity but solution of hydrogen chloride in methylbenzene cannot conduct electricity?

5.By using example,explain how the following factors can determine the selective discharge of ions at the electrodes. a)types of electrodes b)concentration of the ions 6.Describe the electrolysis of the molten lead()bromide

-Substances that can conduct electricity when they are in molten or aqueous solution and undergoes chemical changes. -A process whereby compounds in molten or aqueous solution are broken down into constituent element by passing electricity through them. -Position of ions in the electrochemical series -Concentration of ions in the electrolytes -Types of electrodes used in the electrolysis 1)Inert(Carbon/Platinum) 2)Active(Copper,etc.) Hydrogen Aspects Hydrogen chloride in chloride in water methylbenzene Yes Conduct No electricity This is because in Inference This is because in water,hydrogen methylbenzene,hydrogen chloride is in the chloride exists as neutral form of ions as it molecules.It has no has charge.Hence,it is unable dissociated.The to conduct electricity. hydrogen ion and chloride ion present in the aqueousbsolution carries positive and negative charges repectively.These charges are able to move freely.Hence,it is able to conduct electricity.

1.A crucible is filled with solid lead()bromide PbBr2 until it is half full.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

7.Describe the extraction of aluminium by electrolysis

8.Draw the structure of Daniel Cell and explain how it can produce electricity

2.The apparatus are set up as shown. 3.The solid lead()bromide,PbBr2 is heated util it is completely molten. 4.The circuit is switched on for about 20 minutes.The changes at the anode and the cathode are observed. 5.The circuit is switched off and both electrodes are taken out from the electrolyte.The molten lead()bromide is carefully poured into a beaker. 6.What is left at the bottom of the crucible is observed and recorded. 1.Cryolite,Na2AlF6 is added to aluminium oxide to lower the melting point to about 8500C. 2.The electrodes are made graphite. 3.In the molten state,aluminium oxide will dissociate to aluminum ions and oxygen ions according to the folloeing equation: Al2O3 2Al3++3O24.At the cathode: 4Al3++12e4Al At the cathode: 6O23O2 +12eOverall Equation:4Al3+ + O24Al + 3O2 5.Oxygen will be formed at the anode.It will burn the graphite electrode to form carbon dioxide.Hence,the graphite anode needs to be replaced occasionally. 6.The aluminium is siphohed off as molten aluminium. 1.The solutions are connected through a salt bridge and porous pot Negative terminal Zinc Zinc metal becomes thinner because zinc atom from the electrode loses two electrons to form zinc ion.Zinc electrode dissolved.

Zn

Zn2+ + 2e-

Positive terminal Copper Copper metal becomes thicker because the copper(ll) ions in the copper (ll) sulphate solution receive two electrons to form copper atoms which are later deposited at the copper electrode. Cu2+ + 2eCu

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 Overal ionic equation:Zn + Cu2+ + Cu The flow electrons from the zinc electrodes to the copper electrode results in the flow of alectrical current and thus produces electricity. 9.Draw the structure of a dry cell and explain how it can produce electricity

10.Describe a laboratory experiment to extract lead from lead()oxide by using electrolysis 11.Describe a laboratory experiment to show that types of electrodes affecting the selective discharge of ions in electrolysis of copper()sulphate solution. 12.You are given magnesium ribbon ,copper plate,magnesium nitrate solution ,copper()sulphate solution,connecting wires with crocodile clips,250cm3 beaker,voltmeter and porous pot.Construct a voltaic cell by using the above materials Explain how the voltaic cell can produce electricity.Your answer must include observation and half equetions for

Negative terminal Zinc Zinc metal releases electrons and dissolves to form zinc ions.

Positive terminal Carbon Ammonium ions receive electrons to produce ammnia gas and hydrogen gas 2+ Zn Zn + 2e 2NH4+ + 2e2NH3 + H2 1.Manganese(lV)oxide,MNO2 oxidises the hydrogen gas and minimizes the formation of gas bubbles at the carbon rod when the cell is in use 2MnO2 + H2 Mn2O3 + H2O 2.The flow of electrons from the zinc metal casing (the external circuit) to the carbon rod results in the flow of electrical current and thus produces electricity.

Anode 2O2O2 + 4eOverall ionic equation:

Cathode Pb2+ + 2ePb 2+ 22Pb + 2O 2Pb + O2

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 reaction at anode and cathode 13.Describe a laboratory experiment to construct the electromechanical series of magnesium,copper,zinc and lead

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 1.State the meaning of acid and alkali

2.What is the meaning of strong acid and weak alkali

3.What is neutralization? 4.What is salt? 5.What is precipitate reaction? 6.The pH value of ammonia in water is 9 but the pH value of solution of ammonia in trichlomethane is 7.Explain why pH value of two solutions is different

7.80cm3 if distilled water is added to 20cm3 of 2.0 mol dm-3 solution of HCl.Find the molarity of the dilute solution. 8.In titration ,40cm3 of 0.25 mol dm-3 potassium hydroxide,KOH solution is needed to neutralize 20cm3 of nitric acid,HNO3.Calculate the molarity of the nitric acid,HNO3

Acid -Chemical substances which ionizes in water to produce hydrogen ions,H+ Alkali-Soluble base Strong acid-Acid which ionizes completely with water to form hydrogen ion,H+(HCl) Weak Alkali-Alkali which partially ionizes in water to form hydroxide ion,OH-(NH3) -Reaction of an acid and a base -A compound formed when the hydrogen ion,H+ from an acid is replaced by ametal ion or an ammonium ion. -The method used to prepare insoluble salt where two soluble salt solutions are mixed together. Ammonia in water 9(alkaline) This is because ammonia partially dissociates in water to form hydroxide ions.The presence of hydroxide ions causes the pH value to increase

Aspects pH Inference

Ammonia in trichlomethane 7(neutral) This is because ammonia exists as neutral molecules in trichlomethane.There is no presenc of either hydrogen ion or hydroxide ion that will change the pH value.Thus it is neutral.

M1V1=M2V2 2.0moldm-3(20/100dm3)=M2(100/100dm3) M2=0.4moldm-3 KOH + HNO3 KNO3 + H2O MaVa = a MbVb b 0.25(40) = 1 M(20) 1 3 M=0.5moldm

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 9.Given dilute nitric acid and dilute sulphuric acid have the same concentration of 0.5 mol dm-3.In neutralization experiment,20 cm3 of nitric acid is required to neutralize 20cm3 of sodium hydroxide solution but only 10cm3of sulphuric acid is required to neutralize 20cm3 of sodium hydroxide solution.Explain why. 10.Describe a chemical test to determine a given solution is an acid solution 11.Describe a laboratory experiment to determine the concentration of sodium hydroxide by using titration process.You are given 0.2 mol dm-3 of dilute sulphuric acid,phenolphthalein,burette,pipette and conical flask 12.You are given solid sodium chloride.Describe how to prepare sodium chloride solution of 0.2 mol dm-3 in laboratory by using 250cm3 volumetric flask. 13.Describe the preparation of zinc sulphate 14.Describe the preparation of lead()chloride 15.Describe the preparation of potassium nitrate 16.Solid W is a salt.Describe the tests you would carry out to confirm the presence of zinc ions and nitrate ions in the salt? 17.Solid X is a metal carbonate.Describe the test you would carry out to confirm that X consists of carbonate ions besides heating. 18.You are given four test tubes filled with the solution consists of zinc ions,lead()ions,aluminium ions and

-Sulphuric acid is a diprotic acid,when it dissociates in water to produce two hydrogen ions per mole -Nitric acid is a monoprotic acid,each of it dissociates to form one hydrogen ion. -Thus though same molarity of both acids are used to neutralize the same amount of acid with the same molarity,higher volume of nitric acid would be used as compared to the volume of sulphuric acid used because it nitric acid has half the number of hydrogen ion as compared to sulphuric acid.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 magnesium ions respectively.Describe the tests you would carry out to confirm the ion that present in each test tube. 19.You are given potassium chloride solution,lead()oxide powder and dilute nitric acid.Describe how you would prepare lead ()chloride salt from the given materials. 20.You are given diluye sulphuric acid,copper()nitrate solution and sodium carbonate solution.Describe how you would prepare copper()sulphate salt from given materials.

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 1.What is the meaning of alloy? State the aims of making alloys 2.What is the meaning of composite materials? State the components of the following composite materials: a)Reinforced concrete b)superconductor c)Fibre optic d)Fibre glass e)Photochromic glass

3.State the catalyst,temperature and pressure of the following process: a)Contact process b)Haber process

4.What is the meaning of polymers? Name the monomer of polythene and polyvinyl chloride

-A mixture of 2 or more elements with a certain fixed composition in which the major component is metal(elements combined phusically)

-A structural material that is formed bu combining two or more different substances such as metal,alloys,ceramics,glass and polymers. Composite materials Reinforcement Concrete

Components

Steel bars and concrete(cement,sand and small pebbles) Superconductor Yattrium oxide,barium carbonate,copper(II) oxide Fibre Optics Silica,sodium carbonate,calcium oxide Fibre Glass Glass fibre and polyster(a type of plastic) Photochromic Glass and silver Glass chloride or silver bromide

Process Haber Process Contact Process

Catalyst Iron

Temperature Pressure Production 400-4500C 150Ammonia 300atp 0 Vanadium(v) 500 C 1-21tp Sulphuric oxide,V2O5 acid

-Large molecules made up of many identical repeating sub-unit called monomers which are joined together by covalent bond

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013

5.State four types of glass and their compositions.List the uses of each glass.

Monomer Ethene

Synthetic Polymer Polythene

Chloroethene

Polyvinyl chloride,PVC

Type of Glass Soda-lime Glass

Coponents

Characteristics

Uses

Silicon oxide,sodium oxide,calcium oxide

Good chemical durability,high thermal expansion coefficient,easy to make into different shapes,low melting point Soft and easy to melt,high density,high refractive index

Bottles,window panels,mirror,bulbs,flat galss,glass containers

Lead Crystal Glass

Silicon oxide,sodium oxide,lead oxide,potassium oxide,aluminium oxide Borsilicate Silicon Glass oxide,sodium oxide,calcium oxide,Boron oxide,aluminium oxide Fused Silicon oxide Glass

Art objects,lens,prism,chandeliers

Low thermal Cooking utensils,lab expansion glassware,automobile headlights coefficient,resistant to heat and chemical attact High heat resistant,high transparency,high melting point,resistant to chemical attact

Lab glassware,lenses,telescope,mirrors

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 6.What is -Made from clay,such as kaolin. ceramics?State the properties and list Properties the uses of ceramics. Strong and hard Rust proof and chemicall resistance High melting point Longer lasting and pleasing Hard and not compressible Electric insulators 7.Bronze is an alloy consists of copper Bronze and tin.Explain why Tin atoms are added to the copper atoms bronze is harder arrangement.Tin atoms are bigger than than copper. copper atoms.As a result,the uniformity of the arrangement of copper atoms is disrupted and this prevents the layers of copper atoms to slide aver one another. This made bronze harder than pure copper.

8.Explain how acid rain is formed. Describe how acid rain causes environmental pollution.

9.Explain the industrial process

Uses Building materials Kitchen ware Heat insulator Decorative items Dental and medical uses Electrical items Copper Copper atoms are arranged in an orderly manner and are packed close together.Because the copper atoms are all in the same size,it enables the layer of copper atoms to slide over easily when a force is applied. This shows that pure copper is malleable and soft

Acid Rain: 1.Release of of sulphuric dioxide from chimney of factories,and the burning of petrol in cars. 2.The wind carries the pollutant around the globe. 3.Formation of acid rain: a)Sulphur dioxide in air reacts with water and oxygen to form acid rain. Effects: a)Acid rain coorodes buildings and metal structures. b)Flows into rivers and lakes causing water pollution. i)Lakes and rivers become acidic ii)Fish and other organism die c)Acid rain destroys trees in forest d)Causes soil pollution i)pH of the soil decreases ii)salts are leached out of the top soil iii)roots of trees are destroyed iv)plants die of malnutrition and diseases Process named:Contact process

CHECKLIST FOR SCORING ‘A+’ IN CHEMISTRY SPM 2013 involved in the manufacture of sulphuric acid.Write all the chemical equations involve.

10.Explain the industrial process involved in the manufacture of ammonia gas.Write all the chemical equations involve.

11.Describe a laboratory experiment to prepare ammonium sulphate(ammonium fertilizer) 12.Describe a laboratory experiment to compare the hardness of brass and copper.

Steps involved: 1.Sulphur is burnt in a furnace together with dry air to produce sulphur dioxide. S + O2 → SO2 2.Sulphur dioxide and air are passed over a converter to be converter to sulphur trioxide with the presence of: a)Catalytst:Vanadium(V)oxide,V2O5 b)Temperature:450-5000C c)Pressure:2-3 atp 2SO2 + O2 2SO3 3.Sulphur trioxide is dissolved in concentrated sulphuric acid to form a product called oleum. SO3 + H2SO4 H2S2O7 4.Water is added to oleum to produce concentrated sulphuric acid H2S2O7 + H2O 2H2SO4 Process named:Haber process Steps involved: 1.Nitrogen gas and hydrogen are mixed and scrubbed to get rid of impurities. 2.One volume of nitrogen gas and three volume of hydrogen gas are compressed in the presence of 150-300 atp. N2 + H2 2NH3 3.Then,it goes to the converter.The conditions are: a)Catalyst:Iron b)Temperature:400-4500C 4.The mixture of gas leaves the converter and is cooled until ammonia condense.Only 10% of the mixture will produce ammonia. 5.The rest of the unsuccessful nitrogen and hydrogen gas are then pumpedback to the converter for another chance to react. 6.The ammonia formed are then liquefied and separated to get a better yield.It is then stored under pressure tanks,