CHEMISTRY PAST QUESTIONS AND ANSWERS

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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.

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1 / 60

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Linear

Trigonal planar

Pyramidal

Tetrahedral

2 / 60

Category: CHEMISTRY PAST QUESTIONS

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

rate of diffusion

number of molecules

density

mass

3 / 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

Dissociation energy

Electron affinity

4 / 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

Decreases the value of ∆H

Reduces the time for attainment of equilibrium

Shifts equilibrium position to the right

Increases the collision rate of reactant particles

5 / 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 and beta particles

alpha particles only

alpha particles and gamma rays

6 / 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?

R + P+ → P + R+

S + P+ → P + S +

Q + S+ → S + Q+

S + Q+ → Q + S+

7 / 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

contains more ions

is neutral to litmus

has a higher pH

has a lower molar mass

8 / 60

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

under ultraviolet light

in a box lined with lead

under paraffin oil

in a cool, dark cupboard

9 / 60

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

evolution of gas as it proceeds

positive change in value of enthalpy

loss of heat to the surrounding

attainment of dynamic equilibrium

10 / 60

Category: CHEMISTRY PAST QUESTIONS

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

deliquescent

ionic

a normal salt

a strong electrolyte

11 / 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

smaller surface area

higher molar mass

different chemical properties

protective oxide coating

12 / 60

Category: CHEMISTRY PAST QUESTIONS

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

element in the free state is zero

alkali meta like sodium in its compounds is + 1

atom of a diatomic molecules is + 2

monatomic ion is equal to its charge

13 / 60

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Losing one electron

Sharing one electron

Donating lone pair of electrons

Gaining one electron

14 / 60

Category: CHEMISTRY PAST QUESTIONS

What is responsible for metallic bonding?

Attraction between positive and negative ions

Sharing of electrons between the metal atoms

Attraction between the atomic unclei and cloud of electrons

transfer of electrons from one atom to another

15 / 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?

OH-

H+

Cu2+

CI-

16 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Sulphur

Chlorine

Carbon

Nitrogen

17 / 60

Category: CHEMISTRY PAST QUESTIONS

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

18 / 60

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

oxygen

ethyne

hydrogen

methane

19 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following procedures is suitable for identifying the food colouring added to a pastry sample?

Both electrodes gain electrons

The cathode becomes coated with copper

The anode increases in mass

The blue colour of the solution fades gradually

20 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following occurs when a solution of CuSO₄ is electrolysed using copper electrodes?

Both electrodes gain electrons

The cathode becomes coated with copper

The blue colour of the solution fades gradually

The anode increases in mass

21 / 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

Q emits fewer particles than S

S decays faster than Q

Q is twice as stable as S

22 / 60

Category: CHEMISTRY PAST QUESTIONS

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

free energy of the system

pressure applied to the system

concentration of the reactants

temperature of the system

23 / 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

Boyle's law

Dalton's law

Graham's law

Gay-Lussac's Law

24 / 60

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

sharing two electrons

gaining two protons

gaining two electrons

losing two electrons

25 / 60

Category: CHEMISTRY PAST QUESTIONS

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

metallic

ionic

dative

covalent

26 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

CH4

NH4

HCI

Na+CI

27 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following substances decomposes when an electric current is passed through it?

Zinc rod

Glucose solution

Tetrachlormethane

Hydrochloric acid

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 and ll only

l, ll and lll only

l only

29 / 60

Category: CHEMISTRY PAST QUESTIONS

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

+ 3

+ 6

+ 5

+ 1

30 / 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]

0.318g

0.635g

6.35g

18g

31 / 60

Category: CHEMISTRY PAST QUESTIONS

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

32 / 60

Category: CHEMISTRY PAST QUESTIONS

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

carbon (IV) oxide

oxygen

sulphur (VI) oxide

hydrogen

33 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Race

Height

Age

Mass

34 / 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 temperature is raised

the pressure increased

the volume of the system is increased

a catalysty is intoduced into the system

35 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Group V11 A

Group 11 A

Group 111 A

Group 1 A

36 / 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

a solid is formed and heat is evolved

direct combination is involved and the reaction is endothermic

activation energy is high and a catalyst is required

37 / 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

50cm cube

30cm cube

35cm cube

25cm cube

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

Pauli Exclusion Principle is related to

reversiblility of equlibrium reactions

quantum numbers of electrons

electronegativity values of elements

collision theory of reaction rates

40 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Double decomposition

Action of an acid on a trioxocarbonate (IV)

Neutralisation

Action of an acid on a metal

41 / 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?

42 / 60

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

can be alloyed

are good conductors of electricity

are good conductors heat

can be beaten into sheets

43 / 60

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

contains enzymes

is a mixture

has pH value of 7

is acidic

44 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Zinc ions

Silver

Aluminium ions

Magnesium

45 / 60

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

cassiterite

cryolite

magnetite

bauxite

46 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Hexane

Pentane

Benzene

Propene

47 / 60

Category: CHEMISTRY PAST QUESTIONS

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

paramagnetism

nalleability

ductility

shiny appearance

48 / 60

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanal

propan-1,2,3-triol

ethanoic acid

ethene

49 / 60

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

ethanol

paraffin oil

ammoniacal liquor

kerosene

50 / 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)

the forward reaction will be favoured

the concentration of ammonia will increase

Activation energy will decrease

the reaction will go to completion

51 / 60

Category: CHEMISTRY PAST QUESTIONS

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

difference of +1 in the oxidation numbers of successive members

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

difference of 14 atomic mass units between successive members

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

52 / 60

Category: CHEMISTRY PAST QUESTIONS

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

distillation

filtration

sublimation

evaporation

53 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Electon affinity

Ionization energy

Atomic radius

Electronegativity

54 / 60

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

improve the teste of the water

remove the hardness in the water clear

coagulate sediments in the water

kill harmful bacteria in the water

55 / 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)

Sodium tetraoxosulphate (VI)

Ammonium chloride

56 / 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

57 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Concentrated hydrochloric acid

Dilute sodium chloride solution

Glucose solution

Aqueous copper (ll) tetraoxosulphate (IV)

58 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Redox reaction

Destructive distillation

Nutralization

Dehydration

59 / 60

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

displacement reaction

decomposition

redox reaction

deliquescence

60 / 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)

Acid

Oxidising agent

Bleaching agent

Dehydrating agent

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