2015 WAEC (WASSCE) Chemistry Past Questions & Answers

Question 1

Which of the following polymers in thermosetting?

Accepted Answer

A. Bakelite

Answer

B. Nylon

Answer

C. Polypropene

Answer

D. Polystyrene

Question 2

When a reaction is endothermic,

Accepted Answer

C. Heat content of reactants is less than the heat content of product

Answer

A. Enthalpy change, $\Delta$H is negative

Answer

B. Heat content of a product is less than the heat content of a reactant

Answer

D. The reaction is non-spontaneous

Question 3

Which of the following statements about intermolecular distances and cohesive forces between gas is correct? They are

Accepted Answer

D. Large and negligible

Answer

A. Both large

Answer

B. Both negligible

Answer

C. Constant and negligible

Question 4

Solubility is practically applied in

Accepted Answer

D. Solvent extraction

Answer

A. Fractional distillation

Answer

B. The determination of pH

Answer

C. The determination of saturation in hydrocarbons

Question 5

The gas given off when ethanol reacts with sodium is

Accepted Answer

B. Hydrogen

Answer

A. Carbon(IV)oxide

Answer

C. Methane

Answer

D. Oxygen

Question 6

Consider the following reaction equation: SO42-(aq) + 2H+(aq) + ye- $	o$ SO42-(aq) + H2O(1). The value of y in the equation is

Accepted Answer

A. 2

Answer

B. 3

Answer

C. 4

Answer

D. 6

Question 7

Consider the following equilibrium system: 2SO2(g) + O2(g) $\rightleftharpoons$ 2SO3(g) The addition of more O2(g) to the system will shift the equilibrium position to the

Accepted Answer

A. Right leading to the production of more SO3(g)

Answer

B. Right leading to the production of more SO2(g)

Answer

C. Left leading to the production of more SO2(g)

Answer

D. Left leading to the production of more SO3(g)

Question 8

Which of the following halogens is solid at room temperature?

Accepted Answer

D. Iodine

Answer

A. Bromine

Answer

B. Chlorine

Answer

C. Flourine

Question 9

Which of the following process does not take place in domestic water treatment?

Accepted Answer

C. Neutralization

Answer

A. Chlorination

Answer

B. Flocculation

Answer

D. Sedimentation

Question 10

Consider the following reaction equation: C2H4(g) + 3O2(g) $	o$ 2CO2(g) + 2H2O(g) The volume of CO2(g) produced at s.t.p when 0.05 moles of C2H4(g) was burnt in O2(g) is [Molar Volume of gas = 22.4dm3

Accepted Answer

B. 2.24dm3

Answer

A. 1.12dm3

Answer

C. 3.72dm3

Answer

D. 4.48dm3

Question 11

Which of the following compounds is the least soluble in water?

Accepted Answer

B. CaSO4

Answer

A. CaCl2

Answer

C. NaCl

Answer

D. Na2SO4

Question 12

The compound formed between 14X and 16Y is _______?

Accepted Answer

B. XY2

Answer

A. XY

Answer

C. X2Y

Answer

D. X4Y6

Question 13

The complete hydrogenation of benzene gives

Accepted Answer

B. Cyclohexane

Answer

A. Cyclohexene

Answer

C. Hexene

Answer

D. Hexane

Question 14

Which of the following compounds is a secondary alkanol?

Accepted Answer

C. 3-methylpentan-2-ol

Answer

A. Ethanol

Answer

B. 2-methylbutan-2-ol

Answer

D. Propan-1-ol

Question 15

A metallic ion Z$^{2+}$ with an inert gas structure contains 18 electrons. How many protons are contained in this ion?

Accepted Answer

A. 20

Answer

B. 18

Answer

C. 16

Answer

D. 2

Question 16

Which of the following trioxonitrate(V) salts would decompose on heating to form a metal?

Accepted Answer

B. AgNO3

Answer

A. Cu(NO3)2

Answer

C. Pb(NO3)2

Answer

D. KNO3

Question 17

Which of the following statements about an electrochemical cell is correct? Oxidation occurs

Accepted Answer

A. At the anode

Answer

B. At the cathode

Answer

C. Through the salt bridge

Answer

D. In the aqueous solution

Question 18

How many orbits are contained in an atom with atomic number 13?

Accepted Answer

D. 3

Answer

A. 7

Answer

B. 6

Answer

C. 5

Question 19

The Van der waals' forces are dominant intermolecular forces in_______?

Accepted Answer

B. Chlorine

Answer

A. Ammonium chloride

Answer

C. Sodium chloride

Answer

D. Water

Question 20

Starch could be converted to glucose by the process of

Accepted Answer

D. Hydrolysis

Answer

A. Condensation

Answer

B. Dehydration

Answer

C. Fermentation

Question 21

To which group and period respectively does an element with 15 electrons belong?

Accepted Answer

C. 5 and 3

Answer

A. 3 and 3

Answer

B. 3 and 5

Answer

D. 5 and 5

Question 22

A substance which dissolves readily in organic solvent would

Accepted Answer

A. Be a covalent compound

Answer

B. Have strong electrostatic forces of attraction

Answer

C. have a high melting point

Answer

D. Conduct electricity in molten state

Question 23

A change in the temperature of a saturated solution disturbs the equilibrium between the

Accepted Answer

C. Dissolved solute and the undissolved solute

Answer

A. Undissolved solute and the solvent

Answer

B. Dissolved solute and the solvent

Answer

D. Dissolved solute and the solution

Question 24

The bond formed when ammonia reacts with hydrogen ion to form ammonium ion is

Accepted Answer

B. Dative

Answer

A. Covalent

Answer

C. Hydrogen bond

Answer

D. Ionic

Question 25

Which of the following substances when boiled with aqueous solution of sodium hydroxide would be hydrolyzed? i. Protein ii. Fat iii. Polythene

Accepted Answer

C. i and ii

Answer

A. i

Answer

B. ii

Answer

D. ii and iii

Question 26

A compound has an empirical formular CH2O and molecular mass of 90. [H = 1.00, C = 12.0, O = 16.0]

Accepted Answer

C. C3H6O3

Answer

A. C4H10O2

Answer

B. C3H10O2

Answer

D. C2H2O4

Question 27

The number of unpaired electrons in an atom of an element 8Q is _______?

Accepted Answer

A. 2

Answer

B. 4

Answer

C. 6

Answer

D. 8

Question 28

The number of oxygen molecules present in 16.0g of the gas is ______? [Avogadro's number = 6.02 x 1023]

Accepted Answer

C. 3.01 x 1023

Answer

A. 6.02 x 1022

Answer

B. 6.02 x 1023

Answer

D. 1.51 x 1023

Question 29

The general gas equation was deprived from______?

Accepted Answer

C. Boyle's and Charles' laws

Answer

A. Boyle's and Gay Lussac's laws

Answer

B. Boyle's and Graham's laws

Answer

D. Dalton's atomic theory

Question 30

The correct balanced equation for the reaction between aluminium metal and hot concentrated tetraoxosulphate(VI)acid is ?

Accepted Answer

A. 2AI(s) + 6H2SO4(1) $	o$ AI2(SO4)3(aq) + 6H2O(1) + 3SO2(g)

Answer

B. 2AI(s) + 3H2SO4(1) $	o$ AI2(SO4)3(aq) + 6H2O(1) + 3SO2(g)

Answer

C. 2AI(s) + 4H2SO4(1) $	o$ AI2(SO4)3(aq) + 8H2O(1) + 3SO2(g)

Answer

D. 2AI(s) + 5H2SO4(1) $	o$ AI2(SO4)3(aq) + 8H2O(1) + 3SO2(g)

Question 31

Which of the following oxides is ionic?

Accepted Answer

B. MgO

Answer

A. P4O10

Answer

C. Al2O3

Answer

D. SO2

Question 32

Which of the following pairs of compounds belongs to the same homologous series?

Accepted Answer

D. C2H6 and C4H10

Answer

A. C3H8 and C3H6

Answer

B. C4H10 and C5H10

Answer

C. C2H4 and C4H10

Question 33

Which of the following oxides can be reduced by hydrogen?

Accepted Answer

D. Silver oxide

Answer

A. Aluminium oxide

Answer

B. Magnesium oxide

Answer

C. Sodium oxide

Question 34

The alkaline earth metals have similar chemical properties because________?

Accepted Answer

C. They have the same number of valence electrons

Answer

A. They are in the same period

Answer

B. Their salts are colourless

Answer

D. They are very reactive

Question 35

Which of the following products of biotechnology can be used as a fuel in place of petrol?

Accepted Answer

B. Ethanol

Answer

A. Butane

Answer

C. Ethene

Answer

D. Propanol

Question 36

The negatively charged particle in an atom is the

Accepted Answer

A. Electron

Answer

B. Neutron

Answer

C. Positron

Answer

D. Proton

Question 37

Which of the following gases is monoatomic?

Accepted Answer

A. Argon

Answer

B. Chlorine

Answer

C. Nitrogen

Answer

D. Oxygen

Question 38

An example of an acid salt is

Accepted Answer

C. NaHSO4

Answer

A. CH3COOONa

Answer

B. Mg(OH)Cl

Answer

D. (NH4)2SO4

Question 39

The shape of a molecule of water is _______?

Accepted Answer

A. Non-linear

Answer

B. Octahedral

Answer

C. Pyramidal

Answer

D. Tetrahedral

Question 40

A substance responsible for the sour taste of unripe orange is

Accepted Answer

C. Alkanoic acid

Answer

A. Alkene

Answer

B. Alkanol

Answer

D. Alkanoate

Question 41

Which of the following metals is the strongest reducing agent?

Accepted Answer

C. Potassium

Answer

A. Sodium

Answer

B. Silver

Answer

D. Copper

Question 42

Consider the following reaction equation: CuO(s) + H2(g) $	o$ Cu(s) + H2O(1) Which substance is oxidized?

Accepted Answer

C. H2

Answer

A. Cu

Answer

B. CuO

Answer

D. H2O

Question 43

The shape of a graphite crystal is

Accepted Answer

D. Hexagonal

Answer

A. Tetrahedral

Answer

B. Pyramidal

Answer

C. Octahedral

Question 44

Which of the following gases will diffuse most rapidly? [H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5]

Accepted Answer

C. CH4

Answer

A. Cl2

Answer

B. SO2

Answer

D. C2H6

Question 45

Which of the following pairs of elements forms amphoteric oxides?

Accepted Answer

C. B and Al

Answer

A. Be and Mg

Answer

B. Na and K

Answer

D. Si and Pb

Question 46

Which of the following reactions would take place when concentrated sodium hydroxide solution is added to palm oil?

Accepted Answer

D. Saponification

Answer

A. Esterification

Answer

B. Neutralization

Answer

C. Polymerization

Question 47

Which of the following substances is a heavy chemical?

Accepted Answer

D. Tetraoxosulphate(VI)acid

Answer

A. Ammonia

Answer

B. Barim Hydroxide

Answer

C. Hydrochloric acid

Question 48

The vapour pressure of a liquid depends on: I. Temperature II. rate of condensation III. Cohesive forces holding the particles together.

Accepted Answer

C. I and III

Answer

A. I

Answer

B. I  and II

Answer

D. II and III

Question 49

The following transition metal ions would be coloured in aqueous solution except________?

Accepted Answer

D. Sc3+

Answer

A. Cr3+

Answer

B. Fe3+

Answer

C. Mn3+

2015 WAEC (WASSCE) Chemistry Past Questions

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