CHEMISTRY PAST QUESTION

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SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS APP

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1 / 80

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

reactants stop forming the products

concentrations of the products are greater than those of the reactants

reactants in the system are used up

concentrations of the reactants and products remain constant

2 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Hexane

Propene

Pentane

Benzene

3 / 80

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

coagulate sediments in the water

improve the teste of the water

kill harmful bacteria in the water

remove the hardness in the water clear

4 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Copper (ll) trioxocarbonate (IV)

Copper (ll) oxide

Copper turnings

Copper alloy

5 / 80

Category: CHEMISTRY PAST QUESTIONS

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

S

T

R

Q

6 / 80

Category: CHEMISTRY PAST QUESTIONS

The crystal layers in graphite are held together by

van der Waals' forces

electrostatic forces

covalent bonds

hydrogen bonds

7 / 80

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

a catalysty is intoduced into the system

the volume of the system is increased

the pressure increased

8 / 80

Category: CHEMISTRY PAST QUESTIONS

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

nalleability

ductility

paramagnetism

shiny appearance

9 / 80

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

alktanols

polymers

alkanoates

hydrocarbons

10 / 80

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is a mixture

is acidic

has pH value of 7

contains enzymes

11 / 80

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

hydrogen

ethyne

oxygen

methane

12 / 80

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

decomposition

deliquescence

displacement reaction

redox reaction

13 / 80

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

ionic

a strong electrolyte

14 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Carbon

Chlorine

Sulphur

Nitrogen

15 / 80

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]

122

101

40

53

16 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Ammonium chloride

Sodium chloride

Potassium oxide

Sulphur (IV) oxide

17 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Water

Catalyst

Freezing mixture

Reducing agent

18 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Silver

Aluminium ions

Magnesium

Zinc ions

19 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Electron affinity

lonization energy

Dissociation energy

Heat of atomization

20 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4

2

8

0

21 / 80

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

can be alloyed

are good conductors of electricity

can be beaten into sheets

are good conductors heat

22 / 80

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

30cm cube

50cm cube

35cm cube

25cm cube

23 / 80

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, ll and lll only

l only

l and ll only

24 / 80

Category: CHEMISTRY PAST QUESTIONS

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

NaBr

NaCI

NaI

NaF

25 / 80

Category: CHEMISTRY PAST QUESTIONS

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

rate of diffusion

density

mass

number of molecules

26 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Glucose solution

Zinc rod

Tetrachlormethane

Hydrochloric acid

27 / 80

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

metallic

covalent

ionic

dative

28 / 80

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

ammoniacal liquor

kerosene

paraffin oil

ethanol

29 / 80

Category: CHEMISTRY PAST QUESTIONS

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

gas molecules colliding in a flask

car travelling on a straight line

planets going round the sun

wheelbarrow being pushed

30 / 80

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

loss of heat to the surrounding

evolution of gas as it proceeds

attainment of dynamic equilibrium

positive change in value of enthalpy

31 / 80

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 14 atomic mass units between successive members

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

difference of +1 in the oxidation numbers of successive members

32 / 80

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

33 / 80

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

direct combination is involved and the reaction is endothermic

the reaction is endothermic and occurs at high temperature

a solid is formed and heat is evolved

activation energy is high and a catalyst is required

34 / 80

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 reaction goes to completion at equilibrium

At equilibrium increase in temperature favours the reverse reaction

The forward reaction is exthermic

Pressure has no effect on the equilibrium mixture

35 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Copper and dilute hydrochloric acid

Zinc and concentrated trioxonitrate (V) acid

Water and calcium dicarbide

Magnesium and dilute tetraoxosulphate (VI) acid

36 / 80

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 concentration of ammonia will increase

the forward reaction will be favoured

the reaction will go to completion

Activation energy will decrease

37 / 80

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

cassiterite

cryolite

magnetite

bauxite

38 / 80

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

Gay-Lussac's Law

Boyle's law

Dalton's law

Graham's law

39 / 80

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

electronegativity values of elements

quantum numbers of electrons

collision theory of reaction rates

reversiblility of equlibrium reactions

40 / 80

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

exhibits isotopy

is a component of water

is diatomic

is inflammable

41 / 80

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Tetrahedral

Linear

Pyramidal

Trigonal planar

42 / 80

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

43 / 80

Category: CHEMISTRY PAST QUESTIONS

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

+ 6

+ 3

+ 1

+ 5

44 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Group 1 A

Group 111 A

Group 11 A

Group V11 A

45 / 80

Category: CHEMISTRY PAST QUESTIONS

If the solubility of KHCO₃ is 0.40 mole dm^-3

100.0g

4.0g

40.0g

10.0g

46 / 80

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

Action of an acid on a metal

Neutralisation

47 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Electronegativity

Atomic radius

Electon affinity

Ionization energy

48 / 80

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

high melting point

high molar mass

strong oxidizing ability

solubility in ethanol

49 / 80

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

the volume occupied by them is negligible

they collide without loss of energy

they move about in straight lines

the distances between them are negligible

50 / 80

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

NH4

Na+CI

CH4

HCI

51 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Q is twice as stable as S

S decays faster than Q

Q emits fewer particles than S

S is more stable than Q

52 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4f

4p

4d

4s

53 / 80

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

54 / 80

Category: CHEMISTRY PAST QUESTIONS

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

temperature of the system

degree of disorder in the system

number of molecules

activation energy

55 / 80

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Sharing one electron

Losing one electron

Donating lone pair of electrons

Gaining one electron

56 / 80

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

sharing two electrons

gaining two electrons

gaining two protons

losing two electrons

57 / 80

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

Dehydrating agent

Oxidising agent

Bleaching agent

58 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Race

Height

Age

Mass

59 / 80

Category: CHEMISTRY PAST QUESTIONS

What is oxidized in the reaction represented by the following equation? 3CU + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O

Copper

Hydrogen

Nitrogen

Oxygen

60 / 80

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

Increases the collision rate of reactant particles

Decreases the value of ∆H

Reduces the time for attainment of equilibrium

Shifts equilibrium position to the right

61 / 80

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]

18g

0.635g

0.318g

6.35g

62 / 80

Category: CHEMISTRY PAST QUESTIONS

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

different chemical properties

smaller surface area

higher molar mass

protective oxide coating

63 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Potassium hydroxide

Sodium tetraoxosulphate (VI)

Ammonium chloride

Sodium trioxocarbonate (IV)

64 / 80

Category: CHEMISTRY PAST QUESTIONS

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

carbon (IV) oxide

oxygen

hydrogen

sulphur (VI) oxide

65 / 80

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

66 / 80

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanoic acid

ethanal

ethene

propan-1,2,3-triol

67 / 80

Category: CHEMISTRY PAST QUESTIONS

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

diffusion

combustion

emission

absorption

68 / 80

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?

S + P+ → P + S +

R + P+ → P + R+

S + Q+ → Q + S+

Q + S+ → S + Q+

69 / 80

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-

CI-

H+

Cu2+

70 / 80

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

alpha particles only

alpha and beta particles

beta particles and gamma rays

71 / 80

Category: CHEMISTRY PAST QUESTIONS

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

evaporation

filtration

sublimation

distillation

72 / 80

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

element in the free state is zero

alkali meta like sodium in its compounds is + 1

monatomic ion is equal to its charge

73 / 80

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

is neutral to litmus

has a lower molar mass

contains more ions

74 / 80

Category: CHEMISTRY PAST QUESTIONS

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

1

8

6

12

75 / 80

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 blue colour of the solution fades gradually

The anode increases in mass

76 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hydrated

hygroscopic

insolube

anhydrous

77 / 80

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

0.040dm 3

5.82dm 3

8.62dm 3

78 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Glucose solution

Dilute sodium chloride solution

Concentrated hydrochloric acid

Aqueous copper (ll) tetraoxosulphate (IV)

79 / 80

Category: CHEMISTRY PAST QUESTIONS

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

dative

metallic

covalent

ionic

80 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Both electrodes gain electrons

The blue colour of the solution fades gradually

The anode increases in mass

The cathode becomes coated with copper

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