SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS APP

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1 / 80

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

strong oxidizing ability

high melting point

solubility in ethanol

high molar mass

2 / 80

Category: CHEMISTRY PAST QUESTIONS

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

6

1

8

12

3 / 80

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

deliquescence

redox reaction

decomposition

displacement reaction

4 / 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

Shifts equilibrium position to the right

Increases the collision rate of reactant particles

Reduces the time for attainment of equilibrium

Decreases the value of ∆H

5 / 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 electron shells in the respective atoms

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

6 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Redox reaction

Nutralization

Destructive distillation

Dehydration

7 / 80

Category: CHEMISTRY PAST QUESTIONS

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

ionic

dative

metallic

covalent

8 / 80

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

losing two electrons

gaining two electrons

gaining two protons

sharing two electrons

9 / 80

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is acidic

contains enzymes

has pH value of 7

is a mixture

10 / 80

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

improve the teste of the water

kill harmful bacteria in the water

remove the hardness in the water clear

coagulate sediments in the water

11 / 80

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

in a cool, dark cupboard

in a box lined with lead

under ultraviolet light

under paraffin oil

12 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Copper

Oxygen

Hydrogen

Nitrogen

13 / 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

101

122

53

14 / 80

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

ethyne

hydrogen

methane

oxygen

15 / 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-

Cu2+

H+

CI-

16 / 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

Bleaching agent

Oxidising agent

17 / 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 metal

Neutralisation

Action of an acid on a trioxocarbonate (IV)

Double decomposition

18 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4p

4s

4d

4f

19 / 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

50cm cube

25cm cube

35cm cube

30cm cube

20 / 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

Graham's law

Gay-Lussac's Law

Boyle's law

Dalton's law

21 / 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

deliquescent

ionic

a strong electrolyte

22 / 80

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

they collide without loss of energy

the distances between them are negligible

they move about in straight lines

the volume occupied by them is negligible

23 / 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

activation energy is high and a catalyst is required

a solid is formed and heat is evolved

the reaction is endothermic and occurs at high temperature

24 / 80

Category: CHEMISTRY PAST QUESTIONS

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

nalleability

ductility

shiny appearance

paramagnetism

25 / 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

26 / 80

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Sharing one electron

Losing one electron

Donating lone pair of electrons

Gaining one electron

27 / 80

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

evolution of gas as it proceeds

loss of heat to the surrounding

attainment of dynamic equilibrium

positive change in value of enthalpy

28 / 80

Category: CHEMISTRY PAST QUESTIONS

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

oxygen

sulphur (VI) oxide

carbon (IV) oxide

hydrogen

29 / 80

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

ammoniacal liquor

paraffin oil

ethanol

kerosene

30 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Pentane

Benzene

Propene

Hexane

31 / 80

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

32 / 80

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanoic acid

ethanal

propan-1,2,3-triol

ethene

33 / 80

Category: CHEMISTRY PAST QUESTIONS

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

+ 5

+ 3

+ 1

+ 6

34 / 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

S

Q

R

35 / 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

8.62dm 3

5.82dm 3

0.040dm 3

36 / 80

Category: CHEMISTRY PAST QUESTIONS

The crystal layers in graphite are held together by

van der Waals' forces

electrostatic forces

hydrogen bonds

covalent bonds

37 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Height

Age

Mass

Race

38 / 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 11 A

Group 111 A

39 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Sulphur (IV) oxide

Sodium chloride

Ammonium chloride

Potassium oxide

40 / 80

Category: CHEMISTRY PAST QUESTIONS

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

sublimation

filtration

distillation

evaporation

41 / 80

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

NH4

HCI

Na+CI

CH4

42 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Zinc ions

Magnesium

Silver

Aluminium ions

43 / 80

Category: CHEMISTRY PAST QUESTIONS

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

2

8

0

4

44 / 80

Category: CHEMISTRY PAST QUESTIONS

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

pressure applied to the system

concentration of the reactants

free energy of the system

temperature of the system

45 / 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]

6.35g

0.318g

18g

0.635g

46 / 80

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

are good conductors heat

can be beaten into sheets

can be alloyed

are good conductors of electricity

47 / 80

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

reversiblility of equlibrium reactions

collision theory of reaction rates

quantum numbers of electrons

electronegativity values of elements

48 / 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

ionic

dative

metallic

49 / 80

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

monatomic ion is equal to its charge

alkali meta like sodium in its compounds is + 1

atom of a diatomic molecules is + 2

50 / 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

Pressure has no effect on the equilibrium mixture

At equilibrium increase in temperature favours the reverse reaction

The forward reaction is exthermic

51 / 80

Category: CHEMISTRY PAST QUESTIONS

What is responsible for metallic bonding?

Sharing of electrons between the metal atoms

Attraction between the atomic unclei and cloud of electrons

Attraction between positive and negative ions

transfer of electrons from one atom to another

52 / 80

Category: CHEMISTRY PAST QUESTIONS

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

planets going round the sun

car travelling on a straight line

wheelbarrow being pushed

gas molecules colliding in a flask

53 / 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

contains more ions

has a lower molar mass

is neutral to litmus

54 / 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 and beta particles

beta particles and gamma rays

alpha particles and gamma rays

alpha particles only

55 / 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 cathode becomes coated with copper

The blue colour of the solution fades gradually

The anode increases in mass

56 / 80

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

cassiterite

bauxite

magnetite

cryolite

57 / 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 volume of the system is increased

the pressure increased

the temperature is raised

a catalysty is intoduced into the system

58 / 80

Category: CHEMISTRY PAST QUESTIONS

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

absorption

diffusion

combustion

emission

59 / 80

Category: CHEMISTRY PAST QUESTIONS

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

number of molecules

temperature of the system

activation energy

degree of disorder in the system

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

smaller surface area

higher molar mass

different chemical properties

protective oxide coating

61 / 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 +

S + Q+ → Q + S+

R + P+ → P + R+

Q + S+ → S + Q+

62 / 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

Magnesium and dilute tetraoxosulphate (VI) acid

Water and calcium dicarbide

63 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Hydrochloric acid

Glucose solution

Zinc rod

Tetrachlormethane

64 / 80

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

alkanoates

alktanols

hydrocarbons

polymers

65 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Chlorine

Nitrogen

Carbon

Sulphur

66 / 80

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Pyramidal

Tetrahedral

Linear

Trigonal planar

67 / 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 and ll only

l only

68 / 80

Category: CHEMISTRY PAST QUESTIONS

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

4.0g

40.0g

10.0g

100.0g

69 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Water

Freezing mixture

Catalyst

Reducing agent

70 / 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 anode increases in mass

The blue colour of the solution fades gradually

The cathode becomes coated with copper

71 / 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

Dissociation energy

Heat of atomization

Electron affinity

72 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Q emits fewer particles than S

S decays faster than Q

Q is twice as stable as S

S is more stable than Q

73 / 80

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

exhibits isotopy

is diatomic

is a component of water

is inflammable

74 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Electronegativity

Ionization energy

Atomic radius

Electon affinity

75 / 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

76 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Sodium tetraoxosulphate (VI)

Sodium trioxocarbonate (IV)

Ammonium chloride

Potassium hydroxide

77 / 80

Category: CHEMISTRY PAST QUESTIONS

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

mass

number of molecules

density

rate of diffusion

78 / 80

Category: CHEMISTRY PAST QUESTIONS

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

NaF

NaCI

NaI

NaBr

79 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hydrated

insolube

hygroscopic

anhydrous

80 / 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

Activation energy will decrease

the reaction will go to completion

the forward reaction will be favoured

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SS 3 CHEMISTRY PAST QUESTIONS (WAEC/NECO)

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