CHEMISTRY PAST QUESTIONS

SSCE/NECO/GCE (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.

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1 / 60

Category: CHEMISTRY PAST QUESTIONS

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

carbon (IV) oxide

hydrogen

sulphur (VI) oxide

oxygen

2 / 60

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

gaining two electrons

sharing two electrons

gaining two protons

losing two electrons

3 / 60

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

oxygen

hydrogen

methane

ethyne

4 / 60

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

is a component of water

exhibits isotopy

is inflammable

is diatomic

5 / 60

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

high melting point

high molar mass

solubility in ethanol

strong oxidizing ability

6 / 60

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

reactants in the system are used up

reactants stop forming the products

concentrations of the products are greater than those of the reactants

concentrations of the reactants and products remain constant

7 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Dissociation energy

lonization energy

Heat of atomization

Electron affinity

8 / 60

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

the distances between them are negligible

they collide without loss of energy

they move about in straight lines

the volume occupied by them is negligible

9 / 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 metal

Action of an acid on a trioxocarbonate (IV)

Neutralisation

Double decomposition

10 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?

Aqueous copper (ll) tetraoxosulphate (IV)

Glucose solution

Concentrated hydrochloric acid

Dilute sodium chloride solution

11 / 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]

5.82dm 3

0.896dm 3

0.040dm 3

8.62dm 3

12 / 60

Category: CHEMISTRY PAST QUESTIONS

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

degree of disorder in the system

activation energy

temperature of the system

number of molecules

13 / 60

Category: CHEMISTRY PAST QUESTIONS

The type of chemical bond that exists between potassium and oxygen in potassium oxide is

covalent

ionic

metallic

dative

14 / 60

Category: CHEMISTRY PAST QUESTIONS

What is responsible for metallic bonding?

transfer of electrons from one atom to another

Attraction between positive and negative ions

Sharing of electrons between the metal atoms

Attraction between the atomic unclei and cloud of electrons

15 / 60

Category: CHEMISTRY PAST QUESTIONS

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

See also AGRIC PAST QUESTIONS (SSCE)

insolube

hydrated

hygroscopic

anhydrous

16 / 60

Category: CHEMISTRY PAST QUESTIONS

The property of calcium chloride which makes it useful as a drying agent is that it is

deliquescent

a normal salt

a strong electrolyte

ionic

17 / 60

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

can be beaten into sheets

are good conductors heat

are good conductors of electricity

can be alloyed

18 / 60

Category: CHEMISTRY PAST QUESTIONS

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

ductility

nalleability

paramagnetism

shiny appearance

19 / 60

Category: CHEMISTRY PAST QUESTIONS

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

concentration of the reactants

temperature of the system

pressure applied to the system

free energy of the system

20 / 60

Category: CHEMISTRY PAST QUESTIONS

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

filtration

sublimation

distillation

evaporation

21 / 60

Category: CHEMISTRY PAST QUESTIONS

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

number of molecules

rate of diffusion

density

mass

22 / 60

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

improve the teste of the water

coagulate sediments in the water

remove the hardness in the water clear

kill harmful bacteria in the water

23 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Aluminium ions

Silver

Zinc ions

Magnesium

24 / 60

Category: CHEMISTRY PAST QUESTIONS

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

2

0

4

8

25 / 60

Category: CHEMISTRY PAST QUESTIONS

P _Total = F₁ + P₂ + P ₃ + .........P_n' where P _Total is the pressure of a mixture of gasses. The equation above is an expression of

Graham's law

Gay-Lussac's Law

Boyle's law

Dalton's law

26 / 60

Category: CHEMISTRY PAST QUESTIONS

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

combustion

absorption

emission

diffusion

27 / 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

28 / 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, ll, lll, and IV

l only

l and ll only

l, ll and lll only

29 / 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

activation energy is high and a catalyst is required

direct combination is involved and the reaction is endothermic

a solid is formed and heat is evolved

the reaction is endothermic and occurs at high temperature

30 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Water

Catalyst

Reducing agent

Freezing mixture

31 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Group 111 A

Group 1 A

Group 11 A

Group V11 A

32 / 60

Category: CHEMISTRY PAST QUESTIONS

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

+ 6

+ 1

+ 5

+ 3

33 / 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]

40

122

101

53

34 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Carbon

Nitrogen

Sulphur

Chlorine

35 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Electon affinity

Atomic radius

Ionization energy

Electronegativity

36 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the value of x in the following equation? Cr₂O₇^2- + 14H⁺ + xe- → 2Cr³⁺ + 7H₂O

8

1

6

12

37 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Nutralization

Dehydration

Redox reaction

Destructive distillation

38 / 60

Category: CHEMISTRY PAST QUESTIONS

Consider the reaction represented by the following equation: H_2(g) + 1_2(g) → 2HI_(g). The number of effective collisions of molecules of the reactants decreases as

the pressure increased

the temperature is raised

the volume of the system is increased

a catalysty is intoduced into the system

39 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

Na+CI

HCI

CH4

NH4

40 / 60

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

alkanoates

polymers

alktanols

hydrocarbons

41 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Tetrahedral

Linear

Trigonal planar

Pyramidal

42 / 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?

Cu2+

CI-

OH-

H+

43 / 60

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

in a cool, dark cupboard

under ultraviolet light

under paraffin oil

in a box lined with lead

44 / 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

45 / 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

Oxidising agent

Dehydrating agent

46 / 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

alpha particles and gamma rays

beta particles and gamma rays

alpha and beta particles

alpha particles only

47 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Potassium oxide

Sodium chloride

Sulphur (IV) oxide

Ammonium chloride

48 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following would dissolve in warm dilute H₂SO₄ without effervescence, to give a blue solution?

Copper turnings

Copper (ll) oxide

Copper (ll) trioxocarbonate (IV)

Copper alloy

49 / 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

is neutral to litmus

has a lower molar mass

has a higher pH

contains more ions

50 / 60

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethene

propan-1,2,3-triol

ethanoic acid

ethanal

51 / 60

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

magnetite

cryolite

bauxite

cassiterite

52 / 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+

R + P+ → P + R+

S + P+ → P + S +

S + Q+ → Q + S+

53 / 60

Category: CHEMISTRY PAST QUESTIONS

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

atom of a diatomic molecules is + 2

alkali meta like sodium in its compounds is + 1

monatomic ion is equal to its charge

element in the free state is zero

54 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Race

Mass

Age

Height

55 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following pairs of reagents recat to produce hydrogen?

Water and calcium dicarbide

Magnesium and dilute tetraoxosulphate (VI) acid

Zinc and concentrated trioxonitrate (V) acid

Copper and dilute hydrochloric acid

56 / 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

Pressure has no effect on the equilibrium mixture

The reaction goes to completion at equilibrium

At equilibrium increase in temperature favours the reverse reaction

57 / 60

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

collision theory of reaction rates

reversiblility of equlibrium reactions

electronegativity values of elements

quantum numbers of electrons

58 / 60

Category: CHEMISTRY PAST QUESTIONS

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

4p

4d

4f

4s

59 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Potassium hydroxide

Sodium trioxocarbonate (IV)

Ammonium chloride

Sodium tetraoxosulphate (VI)

60 / 60

Category: CHEMISTRY PAST QUESTIONS

A finely divided from of a metal burns more readily in air than the rod from because the rod has

higher molar mass

different chemical properties

smaller surface area

protective oxide coating

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