CHEMISTRY PAST QUESTIONS

127

SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS

Attempt all 60 questions that are selected from the Chemistry question bank. Use the NEXT, PREV, CLEAR and FINISH buttons to navigate around the CBT.

You have 1 hour to answer all 60 questions.

Goodluck

1 / 60

Category: CHEMISTRY PAST QUESTIONS

A sheet of paper is placed in the path of a beam from a radioactive source. The emissions that pass through the paper consist of

beta particles and gamma rays

alpha particles only

alpha particles and gamma rays

alpha and beta particles

2 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following properties increases down a group in the Periodic Table?

Ionization energy

Electronegativity

Atomic radius

Electon affinity

3 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following compounds dissolves in water to give an alkaline solution?

Sodium chloride

Potassium oxide

Sulphur (IV) oxide

Ammonium chloride

4 / 60

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is acidic

has pH value of 7

contains enzymes

is a mixture

5 / 60

Category: CHEMISTRY PAST QUESTIONS

A reaction is represented by the equation below. A_2(g) + B_2(g) 2AB_(g); ∆H = +X kJmol^-1 Which of the following statements about the system is correct?

The forward reaction is exthermic

At equilibrium increase in temperature favours the reverse reaction

Pressure has no effect on the equilibrium mixture

The reaction goes to completion at equilibrium

6 / 60

Category: CHEMISTRY PAST QUESTIONS

Consider the following equation: Ag⁺ _(aq) + CI-_(aq) → Ag⁺CI- _(s) ; ∆H = _65.7 kJmol^-1. From the equation, it can be deduced that

the reaction is endothermic and occurs at high temperature

direct combination is involved and the reaction is endothermic

activation energy is high and a catalyst is required

a solid is formed and heat is evolved

7 / 60

Category: CHEMISTRY PAST QUESTIONS

What will be the effect of increase in pressure on the following system at equilibrium? 2NH_2(g) N_2(g) + 3H_2(g)

Activation energy will decrease

the reaction will go to completion

the concentration of ammonia will increase

the forward reaction will be favoured

8 / 60

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

is inflammable

exhibits isotopy

is a component of water

is diatomic

9 / 60

Category: CHEMISTRY PAST QUESTIONS

One mole of a compound M(HCO₃)₂ has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16]

101

122

10 / 60

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

gaining two electrons

sharing two electrons

losing two electrons

gaining two protons

11 / 60

Category: CHEMISTRY PAST QUESTIONS

Given that the order of reactivity of four metals is P>Q>R>S, which of the following reactions is feasible?

Q + S+ → S + Q+

S + P+ → P + S +

S + Q+ → Q + S+

R + P+ → P + R+

12 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following statements about ideal gases is/are correct?

I. The cohesive forces between their particles are negligible

ll. The have no definite volume but occupy the volume of their containers

III. They are not compressible

IV. Their particles collide with loss of energy

l only

l and ll only

l, ll, lll, and IV

l, ll and lll only

13 / 60

Category: CHEMISTRY PAST QUESTIONS

The spontaneity of a chemical reaction is determined by the change in the

free energy of the system

concentration of the reactants

temperature of the system

pressure applied to the system

14 / 60

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

reactants stop forming the products

concentrations of the reactants and products remain constant

reactants in the system are used up

concentrations of the products are greater than those of the reactants

15 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

NH4

Na+CI

HCI

CH4

16 / 60

Category: CHEMISTRY PAST QUESTIONS

Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore

S is more stable than Q

S decays faster than Q

Q is twice as stable as S

Q emits fewer particles than S

17 / 60

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

are good conductors heat

are good conductors of electricity

can be beaten into sheets

can be alloyed

18 / 60

Category: CHEMISTRY PAST QUESTIONS

Equal volumes of CO₂ cnd CO at s.t.p have the same

rate of diffusion

mass

number of molecules

density

19 / 60

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

kerosene

ammoniacal liquor

paraffin oil

ethanol

20 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following compounds dissolves in water to form a solution with pH below 7?

Potassium hydroxide

Ammonium chloride

Sodium tetraoxosulphate (VI)

Sodium trioxocarbonate (IV)

21 / 60

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

reversiblility of equlibrium reactions

electronegativity values of elements

quantum numbers of electrons

collision theory of reaction rates

22 / 60

Category: CHEMISTRY PAST QUESTIONS

The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is

oxygen

hydrogen

carbon (IV) oxide

sulphur (VI) oxide

23 / 60

Category: CHEMISTRY PAST QUESTIONS

What does ∆H represent in the following equation ? Cl_(g) + e- → CI- _(g); ∆H = - 363 kJ mol-¹

lonization energy

Heat of atomization

Electron affinity

Dissociation energy

24 / 60

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanal

propan-1,2,3-triol

ethanoic acid

ethene

25 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following lowers the activation energy of a chemical reaction?

Water

Freezing mixture

Reducing agent

Catalyst

26 / 60

Category: CHEMISTRY PAST QUESTIONS

Elements which belong to the same group in the Periodic Table are characterized by

presence of the same number of outermost electrons in the respective atoms

difference of +1 in the oxidation numbers of successive members

difference of 14 atomic mass units between successive members

presence of the same number of electron shells in the respective atoms

27 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following movements can be described as random motion?

car travelling on a straight line

planets going round the sun

wheelbarrow being pushed

gas molecules colliding in a flask

28 / 60

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

they collide without loss of energy

the volume occupied by them is negligible

the distances between them are negligible

they move about in straight lines

29 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following can undergo both addition reactions and substitution reactions?

Benzene

Hexane

Propene

Pentane

30 / 60

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

alkanoates

polymers

alktanols

hydrocarbons

31 / 60

Category: CHEMISTRY PAST QUESTIONS

A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by

distillation

sublimation

filtration

evaporation

32 / 60

Category: CHEMISTRY PAST QUESTIONS

0.10 mol dm^-3 NaCI conducts electricity better than 0.10 mol dm^-3 CH₃COOH because the solution of NaCI

has a higher pH

contains more ions

is neutral to litmus

has a lower molar mass

33 / 60

Category: CHEMISTRY PAST QUESTIONS

30cm³ pf hydrogen at s.t.p combine with 20cm³ of oxygen to form steam according to the following equation 2H_2(g) + O_2(g) → 2H₂O_(g). Calculate the total volume of the gaseous mixture at the end of the reaction

25cm cube

50cm cube

35cm cube

30cm cube

34 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO₂ + O₂ ⇌ 2SO₃; ∆H = - xKJmol-¹

Shifts equilibrium position to the right

Decreases the value of ∆H

Increases the collision rate of reactant particles

Reduces the time for attainment of equilibrium

35 / 60

Category: CHEMISTRY PAST QUESTIONS

What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO₃?

Nutralization

Dehydration

Destructive distillation

Redox reaction

36 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following increases as boiling water changes to steam?

number of molecules

activation energy

degree of disorder in the system

temperature of the system

37 / 60

Category: CHEMISTRY PAST QUESTIONS

The presence of unpaired electrons in an atom of a transition metal gives rise to

nalleability

ductility

shiny appearance

paramagnetism

38 / 60

Category: CHEMISTRY PAST QUESTIONS

What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn_(s) + 2HCI_(aq) → ZnCI _2(aq) + H_2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm³ at s.t.p]

0.896dm 3

5.82dm 3

8.62dm 3

0.040dm 3

39 / 60

Category: CHEMISTRY PAST QUESTIONS

Substances which absorb water from the atmosphere without dissolving in it are said to be

insolube

anhydrous

hygroscopic

hydrated

40 / 60

Category: CHEMISTRY PAST QUESTIONS

How many electrons are removed from Cr^2- when it is oxidized to CrO₄^2-?

41 / 60

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

strong oxidizing ability

high melting point

high molar mass

solubility in ethanol

42 / 60

Category: CHEMISTRY PAST QUESTIONS

Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of

emission

absorption

combustion

diffusion

43 / 60

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

attainment of dynamic equilibrium

evolution of gas as it proceeds

positive change in value of enthalpy

loss of heat to the surrounding

44 / 60

Category: CHEMISTRY PAST QUESTIONS

If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly

covalent

dative

ionic

metallic

45 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following non-metals reacts most readily with metals?

Sulphur

Nitrogen

Carbon

Chlorine

46 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following is not correct about oxidation number convention? The oxidation number of a/an

alkali meta like sodium in its compounds is + 1

element in the free state is zero

atom of a diatomic molecules is + 2

monatomic ion is equal to its charge

47 / 60

Category: CHEMISTRY PAST QUESTIONS

In the Periodic Table, the elements that loss electrons most readily belong to

Group V11 A

Group 111 A

Group 1 A

Group 11 A

48 / 60

Category: CHEMISTRY PAST QUESTIONS

A concentrated solution containing H⁺, Cu²⁺,OH^- and CI^- was electrolysed using platiunm electrodes which of the ions will be discharged at the cathods?

H+

CI-

OH-

Cu2+

49 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following will displace copper from a solution of copper (ll) salt?

Aluminium ions

Magnesium

Silver

Zinc ions

50 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO _2(aq) + 2H₂S_(g) → 3S _(s) + 2H ₂O _(l)

Bleaching agent

Acid

Dehydrating agent

Oxidising agent

51 / 60

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

under ultraviolet light

in a cool, dark cupboard

under paraffin oil

in a box lined with lead

52 / 60

Category: CHEMISTRY PAST QUESTIONS

What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]

0.635g

0.318g

18g

6.35g

53 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the oxidation number of nitrogen in AI(NO₃)₃?

+ 5

+ 3

+ 1

+ 6

54 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?

55 / 60

Category: CHEMISTRY PAST QUESTIONS

Elactrostatic force of attraction between sodium ion and halide ion is greatest in

NaBr

NaCI

NaF

NaI

56 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Trigonal planar

Linear

Tetrahedral

Pyramidal

57 / 60

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

remove the hardness in the water clear

coagulate sediments in the water

improve the teste of the water

kill harmful bacteria in the water

58 / 60

Category: CHEMISTRY PAST QUESTIONS

The atoms of four elements are represented as ₂₀Q, ₁₆R, ₁₀S and ₈T Which of the elements would be unreactive?

59 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following features of a human skeleton can be determined by carbon-dating?

Race

Height

Age

Mass

60 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following methods is suitable for the preparation of an insoluble salt?

Action of an acid on a trioxocarbonate (IV)

Double decomposition

Neutralisation

Action of an acid on a metal

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