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SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS APP

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1 / 80

Category: CHEMISTRY PAST QUESTIONS

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

activation energy

number of molecules

degree of disorder in the system

temperature of the system

2 / 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?

T

R

S

Q

3 / 80

Category: CHEMISTRY PAST QUESTIONS

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

difference of 14 atomic mass units between successive members

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

difference of +1 in the oxidation numbers of successive members

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

4 / 80

Category: CHEMISTRY PAST QUESTIONS

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

combustion

emission

diffusion

absorption

5 / 80

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Tetrahedral

Linear

Pyramidal

Trigonal planar

6 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Freezing mixture

Reducing agent

Water

Catalyst

7 / 80

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

methane

ethyne

oxygen

hydrogen

8 / 80

Category: CHEMISTRY PAST QUESTIONS

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

a normal salt

a strong electrolyte

deliquescent

ionic

9 / 80

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

10 / 80

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

gaining two protons

sharing two electrons

gaining two electrons

losing two electrons

11 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Electon affinity

Ionization energy

Electronegativity

Atomic radius

12 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4

8

0

2

13 / 80

Category: CHEMISTRY PAST QUESTIONS

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

+ 1

+ 6

+ 5

+ 3

14 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Group 1 A

Group V11 A

Group 111 A

Group 11 A

15 / 80

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

hydrocarbons

alkanoates

polymers

alktanols

16 / 80

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

reactants stop forming the products

concentrations of the reactants and products remain constant

concentrations of the products are greater than those of the reactants

reactants in the system are used up

17 / 80

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

is a component of water

is diatomic

is inflammable

exhibits isotopy

18 / 80

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

cassiterite

magnetite

cryolite

bauxite

19 / 80

Category: CHEMISTRY PAST QUESTIONS

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

lonization energy

Electron affinity

Heat of atomization

Dissociation energy

20 / 80

Category: CHEMISTRY PAST QUESTIONS

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

planets going round the sun

gas molecules colliding in a flask

wheelbarrow being pushed

car travelling on a straight line

21 / 80

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

ammoniacal liquor

ethanol

paraffin oil

kerosene

22 / 80

Category: CHEMISTRY PAST QUESTIONS

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

filtration

distillation

sublimation

evaporation

23 / 80

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

solubility in ethanol

strong oxidizing ability

high molar mass

high melting point

24 / 80

Category: CHEMISTRY PAST QUESTIONS

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

100.0g

40.0g

10.0g

4.0g

25 / 80

Category: CHEMISTRY PAST QUESTIONS

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

concentration of the reactants

free energy of the system

pressure applied to the system

temperature of the system

26 / 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 reaction will go to completion

the forward reaction will be favoured

the concentration of ammonia will increase

Activation energy will decrease

27 / 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

alkali meta like sodium in its compounds is + 1

element in the free state is zero

monatomic ion is equal to its charge

28 / 80

Category: CHEMISTRY PAST QUESTIONS

The crystal layers in graphite are held together by

van der Waals' forces

electrostatic forces

hydrogen bonds

covalent bonds

29 / 80

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

displacement reaction

deliquescence

redox reaction

decomposition

30 / 80

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

kill harmful bacteria in the water

remove the hardness in the water clear

improve the teste of the water

coagulate sediments in the water

31 / 80

Category: CHEMISTRY PAST QUESTIONS

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

ionic

metallic

dative

covalent

32 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Propene

Benzene

Pentane

Hexane

33 / 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

contains more ions

has a lower molar mass

is neutral to litmus

has a higher pH

34 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Concentrated hydrochloric acid

Glucose solution

Dilute sodium chloride solution

Aqueous copper (ll) tetraoxosulphate (IV)

35 / 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)

Bleaching agent

Dehydrating agent

Acid

Oxidising agent

36 / 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 and ll only

l only

l, ll and lll only

37 / 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

a catalysty is intoduced into the system

the volume of the system is increased

the pressure increased

the temperature is raised

38 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Destructive distillation

Dehydration

Redox reaction

Nutralization

39 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Copper (ll) oxide

Copper alloy

Copper (ll) trioxocarbonate (IV)

Copper turnings

40 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Hydrogen

Copper

Nitrogen

Oxygen

41 / 80

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

42 / 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 only

alpha particles and gamma rays

beta particles and gamma rays

alpha and beta particles

43 / 80

Category: CHEMISTRY PAST QUESTIONS

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

The anode increases in mass

The blue colour of the solution fades gradually

The cathode becomes coated with copper

Both electrodes gain electrons

44 / 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?

H+

OH-

CI-

Cu2+

45 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hygroscopic

anhydrous

insolube

hydrated

46 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Aluminium ions

Magnesium

Silver

Zinc ions

47 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4d

4f

4s

4p

48 / 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]

40

122

53

101

49 / 80

Category: CHEMISTRY PAST QUESTIONS

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

NaCI

NaF

NaI

NaBr

50 / 80

Category: CHEMISTRY PAST QUESTIONS

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

The anode increases in mass

The blue colour of the solution fades gradually

Both electrodes gain electrons

The cathode becomes coated with copper

51 / 80

Category: CHEMISTRY PAST QUESTIONS

What is responsible for metallic bonding?

Attraction between positive and negative ions

transfer of electrons from one atom to another

Attraction between the atomic unclei and cloud of electrons

Sharing of electrons between the metal atoms

52 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Copper and dilute hydrochloric acid

Water and calcium dicarbide

Zinc and concentrated trioxonitrate (V) acid

Magnesium and dilute tetraoxosulphate (VI) acid

53 / 80

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanoic acid

propan-1,2,3-triol

ethanal

ethene

54 / 80

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

positive change in value of enthalpy

loss of heat to the surrounding

evolution of gas as it proceeds

attainment of dynamic equilibrium

55 / 80

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

the volume occupied by them is negligible

the distances between them are negligible

they collide without loss of energy

they move about in straight lines

56 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Hydrochloric acid

Tetrachlormethane

Glucose solution

Zinc rod

57 / 80

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is acidic

contains enzymes

is a mixture

has pH value of 7

58 / 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

Dalton's law

Graham's law

Gay-Lussac's Law

Boyle's law

59 / 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

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

60 / 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

higher molar mass

different chemical properties

smaller surface area

protective oxide coating

61 / 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?

At equilibrium increase in temperature favours the reverse reaction

The reaction goes to completion at equilibrium

The forward reaction is exthermic

Pressure has no effect on the equilibrium mixture

62 / 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

35cm cube

50cm cube

25cm cube

63 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hydrogen

sulphur (VI) oxide

carbon (IV) oxide

oxygen

64 / 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]

0.635g

0.318g

18g

6.35g

65 / 80

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

66 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Chlorine

Sulphur

Carbon

Nitrogen

67 / 80

Category: CHEMISTRY PAST QUESTIONS

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

ductility

nalleability

shiny appearance

paramagnetism

68 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Race

Mass

Age

Height

69 / 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]

5.82dm 3

0.896dm 3

8.62dm 3

0.040dm 3

70 / 80

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Gaining one electron

Losing one electron

Sharing one electron

Donating lone pair of electrons

71 / 80

Category: CHEMISTRY PAST QUESTIONS

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

8

12

6

1

72 / 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 + Q+ → Q + S+

S + P+ → P + S +

R + P+ → P + R+

Q + S+ → S + Q+

73 / 80

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

HCI

CH4

NH4

Na+CI

74 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Potassium oxide

Ammonium chloride

Sulphur (IV) oxide

Sodium chloride

75 / 80

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 trioxocarbonate (IV)

Sodium tetraoxosulphate (VI)

76 / 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

Decreases the value of ∆H

Reduces the time for attainment of equilibrium

Increases the collision rate of reactant particles

Shifts equilibrium position to the right

77 / 80

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

collision theory of reaction rates

quantum numbers of electrons

reversiblility of equlibrium reactions

electronegativity values of elements

78 / 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

covalent

dative

ionic

metallic

79 / 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)

Neutralisation

Action of an acid on a metal

Double decomposition

80 / 80

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 emits fewer particles than S

Q is twice as stable as S

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