(a) (i) What is diffusion?
(ii) State Charles’ law:
(iii) Sketch a graph to illustrate Charles’ law.
(iv) A given mass of a gas occupied 150 cm3 at 27 °C and a pressure of 1.013 x 105 Nm\(^{-2}\). Calculate the temperature at which its volume will be doubled at the same pressure.
(v) Arrange the three states of matter in order of increasing: (i) kinetic energy; (ii) forces of cohesion.
(b) (i) State Le Chatelier’s principle. (ii) A metal M forms two oxides containing 11.1% and 20.0% of oxygen. Show that these figures agree with the law of multiple proportion.
(c) The table below shows the physical properties of substances A, B and C.
|
Substance |
Melting point/°C | Boiling point/°C |
Solubility in water at 25°C |
| A | 30 | 117 | Insolube |
| B | 31 | 160 | Insoluble |
| C | 1200 | 1200 | Insoluble |
(i) If A and B are miscible when melted and B and C react when heated, describe how a mixture of A, B, and C could be separated.
(ii) When 25.25g of the mixture A, B and C was separated, 7.52 g of A and 8.48 g of B were recovered. Assuming i there was no loss of components during separation, calculate the percentage by mass of C in the mixture
(a) (i) What is the structure of the atom as proposed by Rutherford?
(ii) Distinguish between the atomic number and the mass number of an element.
(iii) Explain briefly why the relative atomic mass of chlorine is not a whole number.
(b) (i) What is meant by first ionization energy?
(ii) List three properties of electrovalent compounds.
(iii) Consider the following pairs of elements: I. \(_9\)F and \(_{17}\)Cl; \(_{12}\)Mg and \(_{20}\)Ca. Explain briefly why the elements in each pair have similar chemical properties.
(c) Explain briefly the following terms using an appropriate example in each case.
(i) homologous series; (ii) heterolytic fission.
(d) State the indicator(s) which could be used to determine the end-point of the following titrations:
(i) dilute hydrochloric acid against sodium hydroxide solution;
(ii) dilute hydrochloric acid against ammonium hydroxide solution;
(iii) ethanoic acid against sodium hydroxide solution.
(e) A solid chloride E which sublimed on heating reacted with an alkali F to give a choking gas G. G turned moist red litmus paper blue. identify E, F and G.
(a)(i) List two characteristics of homologous series.
(ii) Consider the compound represented by the following formula: CH\(_3\)(CH\(_2\))\(_2\)CH\(_3\). I. Which homologous series does the compound belong? II. Write the structures of three possible isomers of the coumpound. III Name the three possible isomers in (a)(ii)II.
(b) Write the structure of the major product formed in each of the following reactions: (i) ethanol with excess acidified potassium tetraoxomanganate (VII);
(ii) excess ethane with chlorine in the presence of sunlight;
(iii) ethanol with propanoic acid in the presence of few drops of concentrated tetraoxosulphate(VI) acid.
(c) Name the major product in each reaction in (b).
(d) Consider the following organic compounds:
(i) Give the IUPAC name of each compound.
(ii) State a chemical test for the functional group in each compound.
(e) An organic compound with relative molecular mass 136 contains 70.57% carbon, 5.90% hydrogen and 23.53% oxygen. Determine its: (i) empopirical formula; (ii) molecular formula. [H= 1.00, C= 12.0, H = 16.0]
(a)(i) Explain briefly the term chemical industry.
(ii) State three factors that should be considered in siting a chemical industry.
(b)(i) Describe briefly twin is extracted from its ore.
(ii) Give two uses of tin.
(c)(i) Name the constituents of cement.
(ii) How does mortar set?
(d)(i) Explain briefly the term pollution.
(ii) Give two examples of air pollutants.
(e) Consider the following reversible reaction which occurred at the temperature of 298K:
N\(_{2(g)}\) + 3H\(_{2(g)}\) \(\rightleftharpoons\) 2NH\(_{3(g)}\); \(\bigtriangleup\)H = —92.37kJ
(a)(i) Define the term hygroscopic.
(ii) Give two difference: between a physical change and a chemical change.
(iii) Using the kinetic theory of gases, explain briefly the Charles’ law.
(b)(i) Arrange the following compounds in order of increasing boiling points: CS\(_2\); CO\(_2\); NaH. Give reasons for your answer.
(ii) Write a balanced chemical equation to illustrate the reaction of chlorine gas with cold dilute sodium hydroxide.
(c) In a certain reaction, 15.0 g of impure magnesium sample reacted with excess hydrochloric acid liberating 8.6 dm\(^2\) of hydrogen gas at s.t.p.
(i) Write a balanced equation for the reaction.
(ii) Calculate the: I. mass of pure magnesium in the sample; I. percentage purity of the magnesium sample; III. number of ions produced in the reaction. [Mg = 24.0; volume at s.t.p. 22.4 dm\(^{-3}\), Avagadro’s constant = 6.02 x 10\(^{23}\)mol\(^{-1}\)]
(a)(i) Define the term standard electrode potential.
(ii) State three factors that affect the discharge of ions during electrolysis.
(iii) State two functions of a salt bridge in an electrochemical cell.
(b) Describe briefly what happens when a solution of copper (II) tetraoxosulphate (VI) is electrolyzed using copper electrodes.
c) Calculate the mass of copper deposited at the cathode when a current of 0.2A is passed through a solution of copper (II) tetraoxosulphate (VI) for 35 minutes using copper electrodes. [H = 1.00, O = 16.0, S = 32.0, Cu = 64.0, IF = 96,500C]
(d)(i) State three characteristics of a catalyst.
ii) Name one manufacturing process in which each of the following metals is used as catalyst: I. iron; II. nickel; Ill. platinum.
c-NA
(a)(i) Define each of the following terms: I. normal salt. II. acid salt.
(ii) Tetraoxosulphate (VI) acid and sodium hydroxide react to produce salt and water. Write a balanced chemical equation fir the formation of: I. a normal salt; II. an acid salt.
(b)(i) Explain briefly the term acid-base indicator.
(ii) Copy and complete the following table.
|
Indicator |
, Colour in acidic medium |
, Colour in basic medium |
|
Methyl orange |
||
|
Phenolphthalein |
(iii) For each of the following titrations, state the most suitable indicator: I. strong acid against strong base; II. strong acid against weak base; iii. weak acid against strong base.
(c) Baking soda and hydrochloric acid react according to the following equation:
NaHCO\(_{3(aq)}\) + HCI\(_{(aq)}\) —> NaCl\(_{(aq)}\) CO\(_{2(g)}\) + H\(_2\)O\(_{(l)}\). Calculate the mass of baking soda that would produce 10g of ccrbon (IV) oxide. [H = 1.00, C = 12.0, 0 = 16.0, Na = 23.0]
(d) Give a reason why a given mass of sodium hydroxide pellets cannot be used to prepare a standard solution.
NaHCO\(_3\) + HCI –> NaCI + CO\(_2\) + H\(_2\)O
84g NaHCO\(_3\) –> 44g CO\(_2\)
Xg –> 10g CO\(_2\)
Xg = \(\frac{84 \times 10}{44}\)
= 19.09g
= 19.1g.
(d) give a reason why a given mass of sodium hydroxide pellets cannot be used to prepare a standard solution: Sodium hydroxide absorbs water/deliquescent and absorbs carbon IV oxide from air/and this would make mass taken unreliable/add to its mass.
(a)(i) What is the common name given to the group VII elements?
(ii) Name the hydrides of the first two elements in group VII.
(iii) State three chemical properties of group VII elements.
(b) Copy and complete the following table:
| Particles |
Number of Neutrons |
Number of electrons |
Number of prontons |
Mass Number |
| W\(^{2+}\) | 12 | 24 | ||
| X\(^{2+}\) | 8 | 16 | ||
| Y | 13 | 27 | ||
| Z | 12 | 11 |
(c)(i) Define each of the followinc processes: I. nuclear fission; II. nuclear fusion.
(ii) Give one use of each process in (c)(i).
(d)(i) List three types of radiation that are produced during radioactivity.
(ii) Arrange the radiations listed in
(d)(i) in order of increasing: I. penetrating power; II. ionizing power.
(a)(i) Define the term functional group.
(ii) Name the functional groups present in the following compound:
(b) Consider the following structure of an organic compound, Q.
(1) Name compound Q.
(ii) Write the balanced equation for the complete combustion of compound Q.
(iii) What type of reaction will compound Q undergo with chlorine?
(vi) Draw the structure of-the alkene that is an isomer of compound Q.
(c) A chemistry student was provided with four samples of organic compounds, A, B, C, and D. Samples A and B each decolourized bromine in tetrachloromethane but only sample B reacted with a solution of ammoniacal silver trioxonitrate (V) to give a white precipitate. Sample D reacted with sodium trioxocarbonate (IV) to liberate carbon (IV) oxide. When heat was applied to the mixture of samples C and D in a test tube and drops of concentrated tetraoxosulphate (VI) acid added, a product with a fruity odour was formed.
(i) Name the family of organic compounds to which samples A, B, C, and D belong.
(ii) State why samples A and B reacted with bromine in tetrachloromethane.
(iii) State the reason why sample B gave a white precipitate with the solution of ammoniacal silver trioxocarbonate (V).
(iv) Give the name o f the reactions between’ samples C and D.
(v) State the two roles of the concentrated tetraoxosulphate (VI) acid in the reaction in (a)(iv).
(d) (i) Describe briefly the production of biogas using a biogas generator.
(ii) State two uses of biogas.
(a)(i) Explain briefly each of the following terms: I. anode; II. cathode.
(ii) Sodium and aluminium are extracted by the electrolysis of molten sodium chloride and alumina respectively. Write balanced equations for the reactions at the anode and cathode during the extraction of: I. sodium; II. aluminium.
(iii) Explain briefly why extraction of aluminium is considered environmentally friendly while that of sodium is not.
(b) Consider the reaction represented by the following equation:
K\(_2\)Cr\(_2\)O\(_7\) + HC1–> KCI + CrCl\(_3\) + H\(_2\)O + Cl\(_2\)
(i) Explain briefly why this reaction is redox.
(ii) Write balanced half equations for the reaction.
(iii) Write the over-all balanced reaction equation.
(c) During the electrolysis of molten Al\(_2\)O\(_3\), a current of 6A was passed through the electrolyte for 1 hr. 30 mins. Calculate the mass of aluminium deposited at the cathode.
(a)(i) Outline the steps involved in the purification of water for town supply.
(ii) Give two cations that can cause hardness in water.
(iii) State two disadvantages of hardness of water.
(iv) List two sources of water pollution.
(b)(i) Explain briefly why water is a good solvent for sodium chloride but not for oil.
(ii) State the function of H\(_2\)SO\(_4\) in each of the following reaction equations:
(i) C\(_2\)H\(_5\)OH\(_{(l)}\) \(\to\) C\(_2\)H\(_{4(g)}\)
(ii) MgO\(_{(s)}\) + H\(_2\)SO\(_4\)\(_{(aq)}\) —> MgSO\(_{4(aq)}\) + H\(_2\)O\(_{(l)}\)
(iii) C\(_{(s)}\) + conc. H\(_2\)SO\(_4\) –> CO\(_{(g)}\) + SO\(_{2(g)}\) + H\(_2\)O\(_{(l)}\)
(c) (i) Give the two products formed when chlorine water is exposed to sunlight.
(ii) I. Which of the compounds is suitable for the preparation of standard alkaline solution?
II. Give a reason for your answer in (c)(ii)I
(a) Define each of the following terms:
(i) ion; (ii) isotopes.
(b)(i) Consider the:element \(_{12}\)Mg and \(_{3}\)Al
I. Write the electron configuration of each element. II. Explain briefly why the first ionization energy of \(_{12}\)Mg is greater than that of \(_{13}\)Al.
(ii) Write the formulae of three different oxides of period 3 elements that react with water.
(c)(i) What are allotropes?
(ii) Name the two crystalline allotropes of carbon.
(iii) Give one industrial use of each allotrope named in (c)(ii).
(d) On warming crystals of sodium chloride with concentrated tetraoxosulphate (VI) acid, a gas was evolved.
(i) List two physical properties of the gas produced.
(ii) Write a balanced equation for the reaction.
(e) A certain chip W used in a circuit of a microcomputer has a mass of 5.68mg. Calculate the amount of W in the microcomputer. [ W = 28 gmol\(^{-1}\) ].
(a)(i) Define ionic bond.
(ii) What type of bond (s) exist (s) in: I. magnesium oxide; II. ammonium ion?
(b) Determine the oxidation number of sulphur in Na\(_2\)S\(_2\)O\(_2\).
(c) State Faraday’s first law.
(d) Give one example each of: (i) acid salt; (ii) base salt.
(e) Name the type of energy change that occurs in each of the following processes
(i) I\(_{2(s)}\) \(\to\) I\(_{2(g)}\)
(ii) Cl\(_{(g)}\) + e\(^{-}\) \(\to\) Cl\(^{-_(g)}\)
(f) State the effect of each of the following aqueous solutions on litmus paper: (i) Na\(_2\)SO\(_{4(aq)}\) (ii) AlCl\(_{3(aq)}\)
(g) Define the term efflorescence.
(h) Give two uses of activated charcoal.
(i) State one use of each of the following processes in the chemical industry: (i) hydrogenation of vegetable oil; (ii) cracking; (iii) esterification.
(j) Calculate the amount of silver deposited in moles when 10920 coulombs of electricity is passed through a solution of a silver salt. [ Faraday constant– 96500 C mol\(^{-1}\)]
(a) Define electrochemical cell.
(b) Aluminium can be prepared commercially by the application of electrolysis. Name the: I. electrolyte used in the process; II. ore from which the electrolyte is obtained; III. electrodes used in the electrolysis.
(ii) Give two reasons why cryolite, NaAl F\(_6\) is added to the electrolyte?
(c)(i) List the two gaseous fuels produced from coke.
(ii) Which of the two gases listed in (c)(i) is a better fuel?
(iii) Give a reason for your answer in (c)(i)
(iv) Write a balanced equation for the production of each gaseous fuel.
(d)(i) For each of the following reactions, state what would be observed when: I. chlorine gas is bubbled through aqueous sodium iodide; II. chlorine gas is passed over heated iron in a hard glass tube; III. aqueous silver trioxonitrate (V) is added to aqueous sodium bromide.
(ii) Write a balanced chemical equation for each of the reactions in (d)(i).
(a)(i) Name two gases that could be used to perform the fountain experiment.
(ii) State the physical property which makes the gases suitable for the experiment in (a)(i)
(b)(i) Define each of the following terms: I. solubility; II. saturated solution.
(ii) State two factors that affect the solubility of a solid in a liquid.
(iii) A salt Z of mass 10.2 g was dissolved in 15.4 cm\(^3\) of distilled water at 40°C. Calculate the solubility of Z in moldm\(^3\) at 40°C. [Mr (Z) = 331].
(c)(i) Town water supplies that have passed through iron pipes contain P and Q ions. In the presence of air, P ions are slowly converted to Q ions.
I. Identify P and Q ions. II. Write a balanced equation for the reaction between P ions, hydrogen ions and oxygen to give Q ions and water.
(ii) Explain briefly a test to confirm the purity of water.
(iii) State the effect of:
I. boiling a temporally hard water. II. adding sodium trioxocarbonate (IV) crystals to permanent hard water;
(iv) Write a balanced equation for the process in (c)(iii)I.
(a)(i) Give three characteristics of homologous series.
(ii) Name two groups of compounds which form such a series.
(b) A saturated organic compound A containing two carbon atoms reacted with ethanoic acid in the presence of a mineral acid to form a compound B with a sweet smell. (i) Name the functional group present in A.
(ii) Draw the structure of A.
(iii) Write a chemical equation to show the formation of B.
(iv) Name the compound B.
(c)(i) Write a balanced equation for the reaction between ethyne and excess bromine.
(ii) Give IUPAC name of the product of the reaction in (c)(i)
(iii) State two conditions under which cracking takes place
(d)(i) Outline the preparation of ethanol from starch.
(ii) Give two properties of starch.
(iii) Give a reason why starch does not reduce Fehlings solution
(iv) Describe briefly a chemical test to confirm the presence of starch.
(a) Consider the following table; (i) Which of the elements:
| Element | Atomic Number | Mass Number |
| J | 9 | 19 |
| Q | 13 | 27 |
| R | 16 | 32 |
| X | 19 | 39 |
| Y | 24 | 52 |
I. is a halogen?
II. is most likely to be attracted by a magnet?
III. belongs to group I?
IV. would readily form an ion with a double negative charge?
(ii) What type of bond would exist between J and X when they combine?
(iii) How many neutrons are there in Q?
(iv) Write the formula of the compound formed when R combines with X.
(v) State the element which exists as diatomic molecule..
(vi) Select the element which belong to the d-block of the periodic table.
(b)(i) Explain briefly the term atomic orbital
(ii) I. State three prostulates of Dalton’s atomic theory.
II. List two limitations of this theory in the study of the atom
(iii) Describe briefly the structure of sodium chloride in its solid state.
(c) A sample of carbon is burnt at a rate of 0.50g per second for 30 minutes to generate heat.
(i) Write a balanced equation for the reaction
(ii) Determine the:
I. volume of carbon (IV) oxide produced at s.t.p.
II. moles of oxygen used up in the process at s.t.p. [C = 12.0, O = 16.0, Molar volume V\(_m\) = 22.4 dm\(^3\)].
(a) Define esterification.
(b) State two properties of plastic.
(c) Name the components of duralumin.
(d) What is meant by each of the following terms?
(i) Raw material.
(ii) Primary product.
(e) State Charles’ law.
(f) List four pieces of protective equipment in the laboratory.
(g) Give two uses of ammonia.
(h) Name the:
(i) process by which lighter hydrocarbons are obtained from heavier ones;
(ii) products formed from the reaction between ethanol and sodium metal.
(i) Determine the oxidation number of sulphur in H\(_2\)SO\(_4\).
(j) Write the IUPAC name for each of the following compounds: (i) NaClO\(_3\); (ii) CuSO\(_4\)5H\(_2\)O.
(a) (i) Define the term fermentation
(ii) Name the catalyst that can be used for this process
(b) Name two factors which determine the choice of an indicator for an acid-base titration
(c) Consider the following reaction equation: Fe + H\(_2\)SO\(_4\) \(\to\) FeSO\(_4\) + H\(_2\). Calculate the mass of unreacted iron when 5.0g of iron reacts with 10cm\(^3\) of 1.0 moldm\(^3\) H\(_2\)SO\(_4\), [Fe = 56.0]
(d) Name one:
(i) Heavy chemical used in electrolytic cells
(ii) Fine chemical used in textile industries
(e) Explain briefly how a catalyst increases the rate of a chemical reaction.
(f) (i) Write the chemical formula for the product formed when ethanoic acid reacts with ammonia
(ii) Give the name of the product formed in (f)(i)
(g) List three properties of aluminum that makes it suitable for the manufacture of drinks cans
(h) State two industrial uses of alkylalkanoates
(i) Name two steps involved in the crystallization of a salt from its solution
(j) List two effects of global warming
(a)(i) Determine the oxidation number of sulphur in Na\(_2\)S\(_2\)O\(_3\)
(ii) Name the allotropes of sulphur.
(iii) State two ways in which the structure of graphite and diamond are similar.
(b)(i) Name two green-house gases.
(ii) State one effect of an increased level of green-house gases on the environment.
(iii) State one source from which nitrogen (I) oxide is released into the environment.
(iv) Write a chemical equation to show the effect of heat on each of the following compounds: I. KNO\(_{3(s)}\) II. AgNO\(_{3(s)}\)
(C)(i)Describe briefly how pure crystals of calcium chloride could be obtained from a solution of calcium chloride
ii) Explain briefly each of the following observations:
I. ammonia gas is highly soluble in water;
II. boiling ploint of chlorine is lower than that of iodine
(d) Consider the reaction represented by the following equation:- 2NaCl + H\(_2\)SO\(_{4(s)}\) \(\to\) Na\(_2\)SO\(_{4(s)}\) + 2HCl\(_{(g)}\)
Calculate the volume of HCl gas that can be obtained at s.t.p. from 5.85 g of sodium. chloride. [ Na = 23.0, Cl = 35.5, Molar volume of gas at s.t.p. = 22.4 dm\(^3\)]
(a)(i) Name a suitable drying agent for the preparation of carbon (IV) oxide in the laboratory.
(ii) Using one chemical test, distinguish between carbon (II) oxide and carbon (IV) oxide.
(b)(i) Describe briefly how oxygen and nitrogen could be obtained separately from air on an industrial scale
(ii) State how a lighted splint can be used to distinguish between samples of oxygen and nitrogen.
(c)(i) Give one reason why bauxite is usually preferred as the ore for the extraction of aluminium.
(ii). List two main impurities. usually present in bauxite.
(iii) State the function of sodium hydroxide solution in the extraction of aluminium from its ore.
(iv) Explain briefly why it is difficult to extract aluminium by chemical reduction of aluminium oxide
(v) Write an equation for the reaction of aluminium oxide with aqueous sodium hydroxide.
(d) (i) The melting and boiling points of sodium chloride are 801 °C and 141.3 °C respectively. Explain briefly why sodium chloride does not conduct electricity at 25°C but does so between 801 °C and 1413 °C.
(ii) State the reason why sodium metal is stored under paraffin oil in the laboratory.
(e)(i) State what would be observed when aqueous sodium trioxocarbonate(IV) is added to a solution containing iron (III) ions
(ii) Write a balanced equation for the reaction in (e)(i).