2017 WAEC (WASSCE) Chemistry Past Questions & Answers

Question 1

Which of the following pairs of gases are pollutants from car exhaust?

Accepted Answer

C. Carbon(II) oxide and Sulphur(IV) oxide

Answer

A. Nitrogen(II) oxide and Carbon(IV) oxide

Answer

B. Carbon(IV) oxide and Nitrogen

Answer

D. Carbon(II) oxide and oxygen

Question 2

The oxidation number of nitrogen in $Pb(NO_{3})_{2}$ is

Accepted Answer

D. +5

Answer

A. +2

Answer

B. +3

Answer

C. +4

Question 3

Which of the following statements is NOT a chemical property of an acid?

Accepted Answer

A. Evolution of ammonia when heated with ammonium salts

Answer

B. Evolution of carbon dioxide gas when added to a trioxocarbonate (IV) salt

Answer

C. Formation of salt and water with alkalis

Answer

D. Formation of salt and hydrogen gas with reactive metals

Question 4

Potassium Chloride solid does not conduct electricity because

Accepted Answer

B. strong cohesive forces make its ions immobile

Answer

A. it is a covalent compound

Answer

C. strong cohesive force makes its molecule immobile

Answer

D. each of potassium and chlorine structures contain noble gas structure

Question 5

Which of the following factors characterize members of the same homologous series?

Accepted Answer

D. Successive members undergo changes in molecular formula by $CH_{2}$

Answer

A. The chemical property change gradually throughout the series

Answer

B. physical properties of members are similar

Answer

C. They have the same molecular formular

Question 6

The seperation of Nitrogen from oxygen using fractional distillation of air is possible because

Accepted Answer

C. of the difference in their boiling points

Answer

A. nitrogen is less dense than oxygen

Answer

B. oxygen is more reactive than nitrogen

Answer

D. they belong to the same period

Question 7

Pauli exclusion principle is related to

Accepted Answer

D. quantum numbers of electrons

Answer

A. quantity of electrons in the valence shell

Answer

B. filling the orbitals with lower energy first

Answer

C. the filling of degenerated orbitals

Question 8

Petroleum is a non-renewable source of energy because it

Accepted Answer

D. cannot be regenerated once used up

Answer

A. is formed naturally

Answer

B. is cheap

Answer

C. can be recycled after use

Question 9

The bond angle in tetrahedral molecules such as tetrachloromethane is

Accepted Answer

B. 109.5°

Answer

A. 180.0°

Answer

C. 105.5°

Answer

D. 90.0°

Question 10

A 0.1$moldm^{-3}$ solution of sodium hydroxide was diluted with distilled water to 0.001$moldm^{-3}$. What is the dilution factor?

Accepted Answer

B. 100.00

Answer

A. 1000.00

Answer

C. 10.00

Answer

D. 0.01

Question 11

Atomic orbital is

Accepted Answer

B. a region around the nucleus where electrons are most likely to be found

Answer

A. the circular path through which electrons revolve round the nucleus

Answer

C. the path around the nucleus through which electrons move

Answer

D. the path around the nucleus through which protons move

Question 12

Halogens generally react with metals to form

Accepted Answer

D. salts

Answer

A. alkalis

Answer

B. acids

Answer

C. bases

Question 13

The name of the compound $C_{4}H_{9}COOC_{3}H_{7}$ is

Accepted Answer

A. propyl pentanoate

Answer

B. pentyl propanoate

Answer

C. butyl propanoate

Answer

D. propyl butanoate

Question 14

Which of the following statements is correct?

Accepted Answer

D. Ionic compounds in solution would conduct electricity

Answer

A. Covalent compounds would readily ionize in solution

Answer

B. Covalent compounds consist of ions

Answer

C. Hydrogen bond is formed between a metal and a non-metal

Question 15

Soluble salts can be prepared by the following methods except

Accepted Answer

C. double decomposition

Answer

A. neutralization

Answer

B. reaction of an acid with trioxocarbonate(IV) salt

Answer

D. reaction of an acid with electropositive metals

Question 16

The property of a chemical reaction that is affected by the presence of a catalyst is

Accepted Answer

A. activation energy

Answer

B. free energy

Answer

C. equilibrium position

Answer

D. enthalpy change

Question 17

Which of the following arrangements indicates the correct decreasing order of ionization energy of period 3 elements?

Accepted Answer

B. Cl, P, Al, Na

Answer

A. Na, Al, P, Cl

Answer

C. Na, P, Cl, Al

Answer

D. Al, Na, P, Cl

Question 18

The oxidation number of X in $XO_{4}^{3-}$ is

Accepted Answer

D. +5

Answer

A. +1

Answer

B. +3

Answer

C. +4

Question 19

The reason for the decrease in the atomic size of elements across a period is that

Accepted Answer

A. nuclear charge increases while the outermost electrons are drawn closer to the nucleus

Answer

B. nuclear charge decreases while the outermost electrons are drawn closer to the nucleus

Answer

C. valence electrons increase across the period while the valence shell remains constant

Answer

D. nuclear charge decreases while the distance of the valence shell from the nucleus is increasing

Question 20

The property of elements which increases down a group of the periodic table is

Accepted Answer

C. ionic radius

Answer

A. electronegativity

Answer

B. electron affinity

Answer

D. ionization energy

Question 21

Consider the following reaction equation: $2NO_{(g)} + O_{{2}{(g)}} 	o 2NO_{{2}{(g)}}$. What is the change in the oxidation number of nitrogen?

Accepted Answer

C. +2 to +4

Answer

A. +2 to 0

Answer

B. +2 to -2

Answer

D. +4 to +2

Question 22

If 0.2g of a salt is required to saturate 200$cm^{3}$ of water at room temperature, what is the solubility of the salt?

Accepted Answer

B. 1.0$gdm^{-3}$

Answer

A. 0.2$gdm^{-3}$

Answer

C. 2.0$gdm^{-3}$

Answer

D. 5.0$gdm^{-3}$

Question 23

The properties of a good primary standard include the following except

Accepted Answer

B. low molecular mass

Answer

A. high molecular mass

Answer

C. high degree of purity

Answer

D. readily available

Question 24

The common feature of reactions at the anode is that

Accepted Answer

C. oxidation is involved

Answer

A. electrons are consumed

Answer

B. ions are reduced

Answer

D. the electrode dissolves

Question 25

In a saturated solution at a given temperature, the undissolved solutes are in equilibrium with

Accepted Answer

B. dissolved solute particles

Answer

A. the solvent

Answer

C. the saturated solution

Answer

D. insoluble solute particles

Question 26

The ionization energy is affected by the following factors except

Accepted Answer

C. ability to attract shared electron(s)

Answer

A. distance of the outermost electron(s) from the nucleus

Answer

B. size of the positive nuclear charge

Answer

D. screening effect of the inner electron(s)

Question 27

Calculate the mass of copper deposited if a current of 0.45A flows through $CuSO_{4}$ solution for 1hour 15mins.   [Cu=64.0, S= 32.0, O =16.0, 1F= 96500C]

Accepted Answer

B. 0.67g

Answer

A. 6.40g

Answer

C. 0.64g

Answer

D. 0.45g

Question 28

Which of the following substances does not have van der Waals' forces?

Accepted Answer

A. Copper

Answer

B. Graphite

Answer

C. Neon

Answer

D. Iodine crystals

Question 29

Classification of alkanols is based on the

Accepted Answer

D. number of alkyl groups bonded to the carbon having the hydroxyl group

Answer

A. number of carbon atoms present in the compound

Answer

B. molecular mass of the compound

Answer

C. molecular formula of the compound

Question 30

Chemical reactions occurs when the colliding reactants have energy that is

Accepted Answer

B. greater than the activation energy

Answer

A. less than the activation energy

Answer

C. greater than the energy of the product

Answer

D. less than the energy of effective collision

Question 31

The number of atoms present in 2.5moles of a triatomic gas is equivalent to   [1mole = $6.02	imes 10^{23}$]

Accepted Answer

D. $2.5	imes 10^{24}$

Answer

A. $2.5	imes 10^{23}$

Answer

B. $1.5	imes 10^{23}$

Answer

C. $1.5	imes 10^{24}$

Question 32

The IUPAC name for the compound $ClCH_{2}CH_{2}OH$ is

Accepted Answer

D. 2-chloroethanol

Answer

A. 1- chloropropanol

Answer

B. 2-chloropropanol

Answer

C. 1-chloroethanol

Question 33

A hydrocarbon contained 14.3% hydrogen. The empirical formula for the hydrocarbon is   [H= 1.0, C= 12.0]

Accepted Answer

B. $CH_{2}$

Answer

A. $CH$

Answer

C. $CH_{3}$

Answer

D. $CH_{4}$

Question 34

The purity of a solid sample can best be determined by its

Accepted Answer

B. melting point

Answer

A. boiling point

Answer

C. conductivity

Answer

D. solubility

Question 35

The use of diamond in abrasives is due to its

Accepted Answer

B. hardness

Answer

A. high melting point

Answer

C. octahedral shape

Answer

D. durability

Question 36

Solubility curve can be used in the determination of the

Accepted Answer

A. amount of crystals formed

Answer

B. amount of solvent that can be recovered

Answer

C. amount of solid drugs in a given solution

Answer

D. temperature of the solution

Question 37

The real harmful effect of the release of chlorofluorocarbons into the atmosphere is that it eventually causes

Accepted Answer

A. excessive ultraviolet light from the sun to reach the earth surface

Answer

B. excessive release of infrared light from the sun to the earth surface

Answer

C. corrosive effect of the chemicals on humans and animals

Answer

D. acidic effect of chemicals on humans

Question 38

When water was added to a white anhydrous substance X, the colour changed to blue. X is

Accepted Answer

A. $CuSO_{4}$

Answer

B. $FeSO_{4}$

Answer

C. $Na_{2}SO_{4}$

Answer

D. $PbSO_{4}$

Question 39

The mass of one mole of $(NH_{4})_{2}CO_{3}$ is   [O=16.0, N=14.0, C=12.0, H=1.0]

Accepted Answer

D. 96.0g

Answer

A. 66.0g

Answer

B. 76.0g

Answer

C. 80.0g

Question 40

The condensation of two units of glucose will produce a dissacharide with the formula $C_{12}H_{22}O_{11}$ which is

Accepted Answer

B. maltose

Answer

A. sucrose

Answer

C. galactose

Answer

D. mannose

Question 41

A primary alkanol has a molecular mass of 60. What is the structural formula of the compound? [C= 12.0, H= 1.0, O= 16.0)

Accepted Answer

D. D

Answer

A. A

Answer

B. B

Answer

C. C

Question 42

When Magnesium reacts with oxygen, heat is

Accepted Answer

C. evolved and the reaction is exothermic

Answer

A. absorbed and the reaction is endothermic

Answer

B. evolved and the reaction is endothermic

Answer

D. absorbed and the reaction is exothermic

Question 43

Which of the following gases is not acidic?

Accepted Answer

D. CO

Answer

A. $SO_{3}$

Answer

B. $NO_{2}$

Answer

C. $Co_{2}$

Question 44

Which of the following metals has the strongest metallic bond?

Accepted Answer

A. $_{13}Al$

Answer

B. $_{19}K$

Answer

C. $_{12}Mg$

Answer

D. $_{11}Na$

Question 45

Which of the following species determines the chemical properties of an atom?

Accepted Answer

A. Electron

Answer

B. Neutron

Answer

C. Nucleus

Answer

D. Proton

Question 46

Which of the following statements about endothermic reaction is correct?

Accepted Answer

D. Heat energy is absorbed

Answer

A. Activation energy is high

Answer

B. A catalyst is required

Answer

C. It occurs reversibly

Question 47

The species with no electron in the 3d-orbital is

Accepted Answer

B. $Sc^{3+}$

Answer

A. $Zn^{2+}$

Answer

C. Cu

Answer

D. $Mn$

Question 48

Graphite and Diamond are similar in that they

Accepted Answer

C. form carbon(IV) oxide on combustion

Answer

A. have octahedral shape

Answer

B. have same density

Answer

D. conduct electricity

Question 49

Fats and oils can be obtained from any of the following sources except

Accepted Answer

A. paraffin oil

Answer

B. animals

Answer

C. groundnuts

Answer

D. palm kernel

Question 50

The following glasswares are used to measure the volume of liquids EXCEPT

Accepted Answer

C. test tube

Answer

A. graduated beaker

Answer

B. pipette

Answer

D. burette

2017 WAEC (WASSCE) Chemistry Past Questions

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