(a) Methane reacts with chlorine under certain condition to produce tetrachloromethane.

(i) State the condition for the reaction

(ii) Name the type of reaction

(iii) Give two uses of methane

(iv) Name one major natural source of methane

 

(b)(i) Mention one similarity between the reaction of ethanol with sodium and that of sodium with water

(ii) Write the structure of two isomers of C\(_3\)H\(_8\)O

(iii) Differentiate between a fine chemical and a heavy chemical

(iv) Give one example of each in (b)(iii) above

 

(c) Two compounds X and Y have the same percentage composition by mass of 92.3% carbon and 7.7% hydrogen. Calculate the:

(i) empirical formula of X and Y;

(ii) molecular formula of each compound if molar mass of X is 26 g and Y is 78g.

 

(d) A protein is boiled for a long time with dilute HCI and a reaction occurred.

(i) State the type of reaction that occurred

(ii) Name the major product formed

(iii) Give the functional groups present in (d)(ii) above.

(a)(i) State one physical method and one chemical method in each case by which the following can be removed:

I. Permanent hardness in water

II. A suspension of CaCO\(_3\) in water.

(ii) Give one disadvantage of hard water.

 

(b) Explain the following observations: (i) Crystals of washing soda become powdery on exposure to air for a long time

(ii) The concentration of chloride ions in 0.02 mol dm\(^{-3}\) calcium chloride solution is not the same s in 0.02 mol dm\(^{-3}\) sodium chloride solution.

(iii) Iron filings corrode faster than iron nails of the same mass.

 

(c)(i) Classify each of the following oxides as acidic, basic, neutral or amphoteric. I. ZnO II. CO III. NO\(_2\)

(ii) Give the formula of the acid anhydride of each of the following: I. H\(_2\)CO\(_3\) II. H\(_2\)SO\(_4\)

(iii) Give the IUPAC name of the following salts: I. COCl\(_2\) II. Mg(NO\(_3\))\(_2\).

 

(d)(i) Mention one pollutant associated with depletion of ozone layer in the atmosphere

(ii) Calculate the volume occupied by 0.125 mole of oxygen at 27°C and a pressure of 2.02 x 105 Nm\(^{-2}\) [I mole of gas occupies 22.4 dm\(^3\) at s.t.p; standard pressure = 1.01 x 105 Nm\(^{-2}\)]

(iii) State one process used for the industrial preparation of oxygen.

(a)(i) Give the reason why copper turnings dissolve in AgNO\(_3\) solution but remain insoluble in Pb(NO\(_3\) )\(_2\) solution.

(ii) Copper turnings of mass 1.06g were placed in 250 cm\(^3\) of 0.20 mol dm\(^{-3}\) AgNO\(_3\). Calculate the amourt of silver ions present. [Cu = 63.5]

(iii) Determine whether all the copper in (a)(ii) above will discolvo in the solution. The equation for the reaction is CU\(_{(S)}\) + 2Ag\(^+_{(aq)}\) --> Ag\(_{(aq)}\) + Cu\(^{2+}_{(aq)}\)

 

(b)(i) List cheicil properties of acids

(ii) Give two large scale uses of HNO\(_3\)

(iii) Write an equation for the action of heat on each of the following compounds: I. Pb(NO\(_3\))\(_2\)

Il. AgNO\(_3\).

 

(c)(i) State what would be observed if a piece of damp blue litmus paper is dropped into a glass jar of chlorine.

(ii) Name the type of reaction which occurs in (c)(i) above.

(iii) Give the property of chlorine which is exhibited in the reaction in (c)(i) above.

(i) Name two products obtained directly from the destructive distillation of coal.

(ii) Give one use of each product named in (d)(i) above.

(a) The electronic configuration of five elements represented by the letters P, Q, R, S and T are indicated below.

P - 1s\(_2\)2s\(_2\)2p\(_2\)

Q 1s\(_2\)2s\(_2\)2p\(_4\)

R 1s\(_2\)2s\(_2\)2p\(_6\)

S - 1s\(_2\)2s\(_2\)2p\(_6\)3s\(_2\)

T - 1s\(_2\)2s\(_2\)2p\(_6\)3s\(_2\)3p\(_5\)

without identifying the elements, state which of them

(i) belongs to group VI in the periodic table;

(ii) is strongly metallic in character;

(iii) readily ionizes by gaining one electron;

(iv) contains two unpaired electrons in the ground state atom

(v) readily loses two electrons during chemical bonding

(vi) Does not paricipates in chemical reactions?

(vii) is an s-block element.

 

(b)(i) Copy and complete the table below as appropriate

Particle	Number of Protons	Number of Electrons	Number of Neutrons
\(^1_1H\)	1	1
\(^{27}_{13}\)Al\(^{3+}\)
\(^{16}_{8}O^{2+}\)			8

 

(ii) Give the reason why atomic radius increases down a group in the periodic table but decreases from left to right in a period.

 

(c)(i) What is meant by the half-life of a radioactive element?

(ii) The nuclide \(^{210}_{84}PO\) loses an alpha 4° particle to form lead. Write an equation for the reaction.

 

(d) State the type of chemical bonding which accounts for each of the following observations:

(i) Chlorine exists as discrete molecules

(ii) Sodium chloride dissolves readily in water;

(iii) CuSO\(_{4(aq)}\) forms a deep blue complex ion with excess NH\(_{3(aq)}\)
 

(a) (i) State three characteristic properties of transition metals.

(ii) What is the oxidation state of manganese In each of the following species? (1) MnCl\(_2\) (II) MnO\(_2\) (III) MnO\(_4^{-}\)

(iii) Explain why manganese conducts electricity in the solid state but manganese chloride conducts only when molten or in solution.

 

(b)(i) The collision theory suggests that for two particles to react, they must collide. What two factors determine whether or not the collision would lead to formation of products?

(ii) Use an energy profile diagram to illustrate what is meant by the enthalpy change (\(\Delta\)H) and the activation energy (E\(_A\)) of a reaction.

 

(c) When few drops of aqueous KSCN are added to a solution of iron (III) salt the following equilibrium is set up:

Fe\(^{3}_{(aq)}\) + 3SCN\(^{-}_{(aq)}\) \(\rightleftharpoons\) Fe(SCN)\(_{3(aq)}\) 

yellow       colourless               deep red

The equilibrium mixture has a pale red colour.

(i) Explain what would happen if more KSCN\(_{(aq)}\) were added to the equilibrium mixture.

(ii) Which of the ions in the equilibrium mixture forms an insoluble hydroxide with NaOH\(_{(aq)}\)? Write an equation for the reaction
(iii) State two changes observed on adding NaOH\(_{(aq)}\) to the equilibrium mixture.