6031q2specimen

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Candidate Name Centre Number Candidate Number

ZIMBABWE SCHOOL EXAMINATIONS COUNCIL
General Certificate of Education Advanced Level

CHEMISTRY 6081/2

PAPER 2

SPECIMEN PAPER 1 hour 30 minutes

Candidates answer on the question paper.
Additional materials:
Data Booklet
Mathematical Tables and/or Electronic Calculator

TIME 1 hour 30 minutes
INSTRUCTIONS TO CANDIDATES FOR EXAMINER’S USE

Write your name, Centre number and candidate number in
the spaces at the top of this page. 1

Answer all questions.
Write your answers in the spaces provided on the question
paper.

INFORMATION FOR CANDIDATES
The number of marks is given in brackets [ ] at the end of
each question or part question.

mil w | N

ol

TOTAL

This question paper consists of 2printed pages.

Copyright: Zimbabwe School Examinations Council, Specimen

©ZIMSEC [Turn over

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Answer all questions

The mass spectrum of a compound consisting of carbon, hydrogen and oxygen only
showed major peaks at m/e values of 15;29;45 and 60. A 3.0 g portion of the

compound was completely burnt in oxygen and produced 6.66 g of carbon dioxide
and 3.6 g of water.

(@@) —_ Calculate the mass of each element in the 3.0 g portion of the compound.

@ carbon

mass of carbon

Gi) hydrogen

mass of hydrogen

Gi) oxygen

mass of oxygen

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&) _ Determine the empirical formula and molecular formula of the compound.

empirical formula

molecular formula

(c) Identify the species responsible for each peak in the mass spectrum.

(d) Draw the displayed structural formula of the compound.

[2]
[Total:10]

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4 Nitrogen dioxide exists in equilibrium with its dimmer,dinitrogentetraoxide.

N2Oaq — 2 NO 44)

The dissociationof N2O4q@is 90 % complete at 100°C and 100 % complete
at 150 °C.

(a) @ Write the K,expression for the reaction and state itsunits.

Kpexpression

units

(ii) 4 moles of N2Ou were heated to 100 °C in a 1 dm*container.

Calculate the number of moles, at equilibrium, of

1. N20a,

2. NO2.

[2]

(iii) Calculate the K-using the values obtained in a(ii).

[1]

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(a) (iv) | State and explain the effect of reducing the temperature to 60 °C,

on the value of Ke.

effect
explanation
(b) @ Draw a dot and cross diagrams for
1. N20a,
2. NO».

(ii) State the bond angleO- N- Oin N2Oa.

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(b) Define the term

0) transition metal,

(ii) complex ion.

[2]
(c) State and explain the
@ observations made whenaqueous ammonia is added to a solution
of copper sulphate until in excess,
(ii) trend in densities of transition elements titanium to copper.
[5]

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(d) Explain why the melting point of calcium is less than that of manganese.

[2]
[Total:10]

(a) Fig. 4.1is a reaction scheme for an organic compound and some of its

products. A volume of 0.56 dm? of hydrogen gas was produced when
3.70 g of the organic compound was reacted with excess sodium metal.

a di-bromo alkane

eXcess
concentrated H, SO,

organic
compound

silver
metal

+
a carboxylic
acid

Fig. 4.1

@ Deduce the relative molecular mass ofthe organic compound.

[2]

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(a) (ii) Deduce, with reasons, the structural formula of the organic compound.

reasons

(b) W and Z are two isomers of butanol
Ww: CH,CH,CH,CH,OH

z: CH,CH,CHOHCH,

@ State the type of isomerism exhibited by the two molecules.

Gi) _— Draw the displayed formula of the third isomer of butanol.

(iii) | Describe how you would distinguish between the two isomers

W and Z.

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(a) Fig.5.1 represents a polymer.

+f 0.¢ <O-CO;- CH-CH, t.

Fig.5.1
@ Draw the structures of the monomers that make up the polymer.
(ii) State
1. one condition used for the formation of the polymer.
2. the type of polymerisation in the formation of the

polymer.

[4]

(b) The structure of acetylcholine, a neurotransmitter substance, is shown in

Fig. 5.2.
0)
| H.C
|
/ \ ware
0 |
H,C cH,
Fig. 5.2

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(b) Give the structural formulae of the products formed when acetylcholine is

@ warmed with water,

(ij) ~~ reacted with ammonia.

[4]
(c) Describe and explain what happens when
@ silver nitrate solution is added to a solution of
tetramethylammonium chloride,
(ii) —_— water is added to tetramethylammonium chloride salt.
[2]
[Total:10]

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(a)

(b)

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@ State Henry’s Law.

[1]

(ii) Give three ways in which Henry’s law is similar to thepartion
law.

1.

[4]

The solubilities of ammonia, carbon dioxide and oxygen in water at a
constant temperature and pressure are in the ratio 29 000: 35 : 1
respectively.

Explain this trend.

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()

12

Calculate the volume in dm? of each of the gases nitrogen, oxygen and
argon which van be boiled off from a saturated solution of air in 1 dm?
of water.

[air contains 78 % nitrogen, 21 % oxygen and 1 % argon. The

respective solubilities of the gases a0.0239, 0.0489 and 0.0530 cm?
dissolved in 1 cm? of water at 0°C and 1 atmosphere pressure.

[2]
[Total:10]

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