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Chemistry paper 1 ,2 & 3

KIRINYAGA WEST SCHOOL BASED FORM IV EXAMINATION 2018

33/1

CHEMISTRY

Paper 1 (THEORY)

1. a) State Le`Chateliers principle

(1mk)

b) When Calcium carbonate is heated the equilibrium shown below is established.

CaCO 3(s)

CaO(s) + CO 2(g)

How would the position of the equilibrium be affected if the pressure is increased. Explain

(2mks)

2. R O

COONa and R O

CH2OSO3Na represent two types of cleansing agents. i)

Name the class of cleansing agent to which each belong.

(1mk)

Cleansing agent

Class

R O COONa

3. 4. 5.

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P

Q

R

S

i) State the compoLnents of the anti-retroviral drug.

(1mk)

ii) On the diagram label:

a) Solvent front line

(2mks)

b) Base line

6. Nitrogen is inert. State two uses of the gas based on this property.

(2mks)

7. a) Write an equation for the reaction that takes place where hydrogen peroxide decomposition in

presence of Manganese (IV) oxide.

(1mk)

1

b) Describe a test that can be used to identify oxygen gas. 8. The salts A1, A2 and A3 were Zinc chloride, Lead (II) nitrate and Magnesium sulphate.

Chemistry paper 1 ,2 & 3

(2mks)

Substance

Silver nitrate

Barium chloride

Hydrochloric

Salt A1

No ppt

White ppt

No ppt

Salt A2

White ppt

No ppt

No ppt

Salt A3

No ppt

White ppt

White ppt

(3mks)

Identify Salt A1 __________________________________________________________________________ Salt A2 ___________________________________________________________________________ Salt A3 ___________________________________________________________________________ 9. Study the information in the table below and answer the questions that follow:-

Number of carbon atoms per molecule

Relative molecular mass of hydrocarbon

10. 11.

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Water

Solution D

pH = 5.5

i) Identify B and C .

(2mks)

ii) Write an equation for the reaction that takes place when C reacts with water.

(2mks)

12. The date given below was recorded when metal E was completely burnt in air. E is not the actual

symbol

of the metal. (R.A.M. E = 56, O = 16.0)

Mass of empty crucible and lid = 11.34g

Mass of crucible, lid and metal E = 11.452g

Mass of crucible, lid and metal oxide = 11.500g

2

a)

b) 13. a)

Chemistry paper 1 ,2 & 3

Determine the mass of i) Metal E ii) Oxygen Determine the empirical formula of the metal oxide.

(1/2mk) (1/2mk) (2mks)

In the extraction of sodium metal, calcium chloride metal is added to the sodium chloride.

Explain the role of calcium chloride in the process.

(1mk)

b) State two properties of sodium metal that makes it possible for it extracted from it ore.

(2mks)

14. If it takes 30 seconds for 100cm3 of carbon (IV) oxide to diffuse across a porous plate, how long

will it take 150cm3 of nitrogen (IV) oxide to diffuse across the same plate under similar conditions.

(C = 12.0, N = 14.0, O = 16.0)

(3mks)

15. Study the information in the table below and answer the questions that follow.

The letters do not represent the actual symbols of the element.

Element

Electrical conductivity Ductility

Action of water

Z

Good

Good

No reaction

X

Good

Poor

No reaction

W

Good

Good

Reacts

16. 17.

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cooled

(1mk) (1mk) (1mk)

to 00C. (1mk) (1mk) (1mk)

Al

Al

Cl

Cl

Cl

a) Identify the bonds labelled L and N.

N

b) How many electrons are used for bonding in the molecules?

18. The table below shows the first ionization energies of elements S1 and S2.

(2mks) (1mk)

Element

Ionisation Energy kJ/mol

S1

494

S2

418

a) What is ionization energy? b) Which of the two elements is the least reactive? Explain.

(1mk) (2mks)

3

19. The nature isotopes of silicon occur in the following percentages by mass.

Isotope

Percentage by mass

Silicon ? 28

92

Silicon ? 29

5

Silicon ? 30

3

Chemistry paper 1 ,2 & 3

a) Calculate the relative atomic mass of silicon. b) Identify the most stable isotope of silicon. 20. The following data gives pH values of solution I, II, III.

Solutions

pH

(2mks) (1mk)

I

12

II

7

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(11/2mks) (1/2mk) (1mk)

(1mk) (1mk)

iii) State one observation likely to be made when product M is reacted with hot solid copper (II)oxide.

(1mk)

22. Sulphur consists of two allotropes.

a) Name the allotropes

(1mk)

b) Concentrated sulphuric (VI) acid reacts with sugar and zinc. State property of the acid shown in

each case.

(1mk)

i) Sugar

ii) Zinc

4

23. A radioactive material emitted radiations as shown below.

(+)

+

A

B C (-)

Chemistry paper 1 ,2 & 3

i) Identify A and B

(1mk)

ii) Which radiation

a) has the lowest ionizing power?

(1mk)

b) contains helium particles?

(1mk)

24. Below are heats of combustion of carbon, hydrogen and ethanol.

25.

26. 27.

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Porous pot

Beaker 1

Beaker 2 State and explain the observation that would be made in glass tube if beaker 2 was filled with air.

28. The process in which a gas changes directly into a solid is called ____________________

(3mks) (1mk)

5

Chemistry paper 1 ,2 & 3

KIRINYAGA WEST 233/2 CHEMISTRY Paper 2 (THEORY) SECTION A 1. a) The diagram below shows a set-up that was used to prepare oxygen gas and passing it over a

burning candle. The experiment was allowed to run for sometime.

2.

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b) Write a chemical equation for the formation of the product (a) above.

(1mk)

c) i) Name the filtrate collected after sodium carbonate was added.

(1mk)

ii) Name the white powder.

(1mk)

d) Write chemical equation for the reaction between product in (a) and acid.

(1mk)

e) Name the ions present in the filtrate after addition of sodium carbonate.

(1mk)

f) Write an ionic equation to show the formation of the white powder.

(1mk)

g) If the white powder is strongly heated explain what happens to its mass.

(2mks)

6

Chemistry paper 1 ,2 & 3

3. Use the information below on standard electrode potentials to answer the questions that follow.

Electrode reaction

C 2+ (aq) + 2 e -

C(s)

D 2+ (aq) + 2e-

D(s)

E+ (aq) + e-

E(s)

Fe 2+ (aq) + 2e-

Fe(s)

G

2 +

(aq)

+ 2e-

G(s)

1/2H 2(g) + e -

H-(aq)

1/2K 2(g) + e -

K-(aq)

L+ (aq) + e-

1/2L2

E Volts 0.34 +0.44 -2.92 -2.71 -0.14 +2.87 +1.09 0.00

bac)))ii)Di1GRRSSi)C0ntteerirrv0adaaaooIlewcissdnnccoomeggruannaeneetl3n_aaetss_oitsd_ttfte_foh_yorGPl_ne2tae_xh_tdslmba_hiafe._ude_lest_ociles_izs_niwu.aK_nimt_lnur_gdpo_og.m_ihfn_faaf_auoogg_ge_grfree_lri_eeasnc_tmn_chtmt_(tt_ero-r_Ve_-oro_c_deI_n_fe_)_u_s_laf__cal._r__ei_ccf_n__io_ee_dg__rl__l_mp_w_a__fa_g_eo_a_s_e_drs__tn_m__b_ept___ely_a_a_ed__np_c_c__dtb_eo__r_y_nr_os__s_n_ltc_,_ry_e_oo__zvc__nn_ei_t_s_nigd__n_i_eet__gu_:_cs___swt_th_i_i__onnaw____xglg__wf__i_d_ht_c_.h_i_fae_B_rze_l_le_i_fl_un_ses__c_eg_lk__Cbet__Pc_l_a_ul_sG_ga_sl_p_ean_e__oa_pnd_rt__fi_esat__nD_.pE_s__u_rL_.t__eap_m___sn_a_e__d_p_n___e_Dt__e_r___.ds____O.__bc___n_yo____m__tt__hh____ee______dd____ii__aa___gg____rr___aamm

(2mks)

(1mk) (3mks) below.

2M H2SO4

i) Write an equation for the reaction that produces gas L.

(1mk)

ii) Describe the test for gas K.

(2mks)

iii) Account for the difference in volume of gases produced at the electrodes.

(2mks)

iv) If 100cm3 of 2m ethanoic acid was used in place of sulphuric acid comment on brightness of the bulb. (2mks)

7

Chemistry paper 1 ,2 & 3

4. The grid below represents part of the periodic table. Study it and answer the questions that follows.

B F G

A

C

D

E

H

i) Select the element that can form an ion with a charge of -2. Explain.

(2mks)

ii) What type of structure would the oxide of C have? Explain.

(2mks)

iii) Compare reactivity of H and E. Explain.

(2mks)

b) 1.3g of B reacts completely when heated with 1.21 litres of chlorine gas at s.t.p.

(1 mole of gas at s.t.p. occupies 22.4 litres)

c) 5.

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G

(1mk) (2mks)

(1mk) (1mk)

To storage

i) Write the equation for the reaction in which sulphur (IV) oxide gas is produced.

(1mk)

ii) Why is it necessary to keep the gases pure and dry?

(1mk)

iii) Describe the process that takes place in chamber G.

(1mk)

iv) Name the gases that escapes into the environment.

(1mk)

v) State and explain the harmful effect on the environment of one of the gases named in (iv) above. (1mk)

vi) Give one reason why it is necessary to use a pressure of 2-3 atmosphere and not more.

(1mk)

b) i) Complete the table below to show the observation made when concentrated sulphuric acid

is added to the substances shown.

(2mks)

Substance

Observations

Iron filings

Crystals of white sugar

ii) Give reasons for the observations made using I) Iron fillings

(1mk) 8

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