Name: …………………………………………………………
Admn No.:……………………...............
School: ………………………………………………………….
Candidate’s Sign:……………………...
Date:…..……………..……………………………........................
233/2
CHEMISTRY
PAPER 2
(THEORY)
JULY/AUGUST - 2015
TIME: 2 HOURS
BUTERE EAST JOINT EVALUATION EXAM – 2015
Kenya Certificate of Secondary Education (K.C.S.E)
CHEMISTRY
PAPER 2
2 HOURS
INSTRUCTIONS TO THE CANDIDATES

Write your name and indexnumberin the spaces provided above.

Sign and write the date of examination in the spaces provided.

Answer all questions in the spaces provided.

KNEC mathematical table and silent non-programmable electronic calculators may be used.

All workings must be clearly shown where necessary.

Candidates should answer the questions in English.
For Examiner’s Use Only:QUESTION
Total
MAXIMUM SCORE
1
12
2
10
3
13
4
11
5
11
6
11
7
12
CANDIDATE’S SCORE
80
This paper consists of 8 printed pages.
Candidates should check the question paper to ascertain that all pages are printed as indicated.
And that no questions are missing.
©Butere East Joint Exam 2015
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Chemistry 233/2
1.
The diagram below shows the process of manufacturing sodium carbonate using ammonia soda
process. Study it and answer the questions that follow.
(a) Name gases A and B.
(2 marks)
A………………………………………………………………………………………………
B………………………………………………………………………………………………
(b) Name liquid C and solid D.
(2 marks)
C………………………………………………………………………………………………
D………………………………………………………………………………………………
(c) Write equations of the reactions in:
(2 marks)
Tower P ………………………………………………………………………………………..
Tower R ………………………………………………………………………………………..
(d) Name the product T formed at chamber R and give one of its uses.
(2 marks)
…………………………………………………………………………………………………………..
…………………………………………………………………………………………………………..
2.
The set-up below was used to prepare and collect gas X. During the experiment cleaned magnesium
ribbon was strongly heated before heating the wet glass wool.
(a) Name gas X………………………………………………….
(1 mark)
(b) Why is magnesium ribbon cleaned before it is used?
(1 mark)
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Chemistry 233/2
…………………………………………………………………………………………………………
(c) State one observation that would be noted in the reaction tube.
(1 mark)
………………………………………………………………………………………………………….
(d) Write the equation for the reaction in the reaction tube.
(1 mark)
…………………………………………………………………………………………………………..
(e) State one industrial use of the solid product formed in the reaction tube.
(1 mark)
…………………………………………………………………………………………………………
(f) What precaution should be taken at the end of experiment? Explain.
(2 marks)
…………………………………………………………………………………………………………..
(g) At the end of the experiment 96.0cm3 of gas X were collected at 10°C and 1 atmosphere
pressure. (Mg = 24, M.G.V = 22.4, T =0°C at stp, P = 1 atmosphere at sip).
(i) Determine the volume gas X would occupy at s.t.p?
(2 marks)
………………………………………………………………………………………………………..
………………………………………………………………………………………………………...
(ii) Calculate the mass of magnesium ribbon used Mg = 24.
(2 marks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
3.
Air was passed through several reagents as shown in the flow chart below.
Gas p
Air
Electrostatic
Concentrated
Sodium
hydroxide
Excess heated
Copper turnings
Excess
heated
Magnesium
Compressor
Fractionating column
Nitrogen
Argon
(-1960C)
(-1860C)
C (-1830C)
(a) Name the major components of air.
(2mks)
…………………………………………………………………………………………………………..
…………………………………………………………………………………………………………...
(b) Write an equation for the reaction which takes place in the chamber with:
©Butere East Joint Exam 2015
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Chemistry 233/2
(i) Concentrated sodium hydroxide.
(1mk )
…………………………………………………………………………………………………………
(ii) Excess heated copper turnings.
(lmk)
…………………………………………………………………………………………………………
(iii) Excess heated magnesium powder.
(1mk
…………………………………………………………………………………………………………
(c) Name onegas which escapes from the chamber containing magnesium powder. Give a reason for
your answer.
(2mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(d) Name the substance that was eliminated by electrostatic precipitation.
(lmk)
…………………………………………………………………………………………………………
(e) Name a reagent that can be used in place of concentrated sodium hydroxide.
(1 mk)
…………………………………………………………………………………………………………
f) Name substance C.
(lmk)
…………………………………………………………………………………………………………
(g) State three uses of gas C.
(3mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
4.
Study the information below and answer the questions that follow:
Formula of the chloride
Nacl
MgCl2 MCl2
SiCI4
PCI3
SCI2
M.P(0C)
801
714
-
-70
-91
-80
Formula of the oxide
Na20
MgO
A1203
Si02
P4010 SO2
Cl207
M.P(0C)
1190
3080
2050
1730
560
-90
-73
(a) Aluminium chloride AlCl3 has an unexpected bond type and structure.
(i) State the type of bond and the structure in AlCl3.
Bond type................................................................................................................................ (lmk)
Structure.................................................................................................................................. (lmk)
(ii) What type of bonding would AlCI3be expected to have why?
(lmk)
…………………………………………………………………………………………………………
(iii) Why is the melting point of AlCI3 not indicated in the table above?
(1mk
…………………………………………………………………………………………………………
©Butere East Joint Exam 2015
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Chemistry 233/2
(b) A piece of blue litmus paper is placed in a solution of sodium chloride and a solution of
aluminium chloride. Explain what would be observed in each case.
Sodium chloride solution
(lmk)
…………………………………………………………………………………………………………
Aluminium chloride solution
(2mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(c) Explain the large difference in the melting point of the compound of formula MgO and P4O10
(2mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
(d) Write down the equations for the reaction between the compounds of formula Na2O and water.
(1mk)
…………………………………………………………………………………………………………
(e) Silicon(IV) chloride gets hydrolyzed by water Write a balanced equation for this reaction.(lmk)
…………………………………………………………………………………………………………
5.
A compound Z has a molar mass of 56g and contains 853% carbon and 14.3% hydrogen by mass.
(C = 12, H = 1)
a) i) Determine the molecular formula of compound Z.
(2 marks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
ii) Give the structural formula of the sixth member of the homologous series to which Z belongs.
(1 mark)
…………………………………………………………………………………………………………
b) Draw and name 2isomers of Z.
(2 marks)
c) Compound Z reacts with a few drops of acidified potassium chromate (VII) solution.
i) State the observation made during the reaction.
(1 mark)
…………………………………………………………………………………………………………
ii) Name the organic product formed in the reaction on (c) above.
©Butere East Joint Exam 2015
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Chemistry 233/2
(1 mark)
…………………………………………………………………………………………………………
d) Z reacted with liquid bromine in the dark (room conditions).
i) State the observation made duringthe reaction.
(1 mark)
…………………………………………………………………………………………………………
ii) Write the equation for above.
(1 mark)
…………………………………………………………………………………………………………
iii) Name the organic product formed in (d) above.
(1 mark)
…………………………………………………………………………………………………………
iv) State the type of reaction in (d) above.
(1 mark)
…………………………………………………………………………………………………………
6.
Use the table below to answer the questions that follow. (The letters are not actual symbols of the
elements)
Element
Atomic number
M.P (0C)
A
11
97.8
B
13
660
C
14
1410
D
17
-101
E
19
63.7
a) Write the electronic arrangement for the ions formed by the elements B and D
(2mks)
…………………………………………………………………………………………………………
b) Select an element which is
i) A poor conductor of electricity.
(l mk)
…………………………………………………………………………………………………………
ii) The most reactive non-metal.
(1 mk)
…………………………………………………………………………………………………………
c) To which period of the periodic table does element E belong?
(l mk)
…………………………………………………………………………………………………………
d) Element E losses its outermost electron more readily than A. Explain.
(2mks)
…………………………………………………………………………………………………………
e) Use dots (•) and crosses (x) to represent the valence electrons and show the bonding in the
compound formed between element C and D.
©Butere East Joint Exam 2015
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f) Explain why the melting point of element B is higher than that of elementA
(2mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………..
g) Write an equation for the reaction that takes place between element A andwater.
(1 mk)
…………………………………………………………………………………………………………
h) Describe how a solid mixture of the sulphate of element E and Lead (II)sulphate can be
separatedinto solid samples.
(3mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
7.
Study the flow chart below and answer the questions which follow:
(i) Give one source of the following raw materials.
(2mks)
Nitrogen gas ………………………………………………………………………………………
Hydrogen gas ……………………………………………………………………………………..
ii) State two conditions required in process I.
(2mks)
…………………………………………………………………………………………………………..
…………………………………………………………………………………………………………..
(iii) Name:
©Butere East Joint Exam 2015
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Catalyst P……………………………………………………………………………………………
Gas M…………………………………………………………………………………………………
(iv) Write chemical equations for;
(2mks)
(a) Formation of gas M
…………………………………………………………………………………………………………
(b) The reaction in the absorption tower.
…………………………………………………………………………………………………………
(v) Describe how you would test if a given liquid is a nitrate.
(2mks)
…………………………………………………………………………………………………………
(vi) Give three uses of nitric acid
(3mks)
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
©Butere East Joint Exam 2015
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