SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS APP

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1 / 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

2 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Carbon

Nitrogen

Sulphur

Chlorine

3 / 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

Decreases the value of ∆H

Reduces the time for attainment of equilibrium

Increases the collision rate of reactant particles

4 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Ammonium chloride

Sulphur (IV) oxide

Potassium oxide

Sodium chloride

5 / 80

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

solubility in ethanol

high melting point

high molar mass

strong oxidizing ability

6 / 80

Category: CHEMISTRY PAST QUESTIONS

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

number of molecules

mass

rate of diffusion

density

7 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Neutralisation

Action of an acid on a metal

Action of an acid on a trioxocarbonate (IV)

Double decomposition

8 / 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

a solid is formed and heat is evolved

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

9 / 80

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

coagulate sediments in the water

kill harmful bacteria in the water

improve the teste of the water

remove the hardness in the water clear

10 / 80

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

quantum numbers of electrons

electronegativity values of elements

reversiblility of equlibrium reactions

collision theory of reaction rates

11 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Height

Age

Mass

Race

12 / 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

has a higher pH

is neutral to litmus

13 / 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

Boyle's law

Graham's law

Dalton's law

Gay-Lussac's Law

14 / 80

Category: CHEMISTRY PAST QUESTIONS

What is responsible for metallic bonding?

Attraction between the atomic unclei and cloud of electrons

Sharing of electrons between the metal atoms

transfer of electrons from one atom to another

Attraction between positive and negative ions

15 / 80

Category: CHEMISTRY PAST QUESTIONS

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

+ 5

+ 3

+ 6

+ 1

16 / 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)

17 / 80

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

methane

ethyne

hydrogen

oxygen

18 / 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 alloy

Copper turnings

19 / 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

protective oxide coating

smaller surface area

20 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Glucose solution

Concentrated hydrochloric acid

Aqueous copper (ll) tetraoxosulphate (IV)

Dilute sodium chloride solution

21 / 80

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

the volume occupied by them is negligible

they move about in straight lines

they collide without loss of energy

the distances between them are negligible

22 / 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

23 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hydrogen

carbon (IV) oxide

sulphur (VI) oxide

oxygen

24 / 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

ionic

covalent

metallic

dative

25 / 80

Category: CHEMISTRY PAST QUESTIONS

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

hydrated

hygroscopic

insolube

anhydrous

26 / 80

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

polymers

hydrocarbons

alktanols

alkanoates

27 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Heat of atomization

Electron affinity

lonization energy

Dissociation energy

28 / 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

8.62dm 3

0.896dm 3

0.040dm 3

29 / 80

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

can be beaten into sheets

are good conductors heat

can be alloyed

are good conductors of electricity

30 / 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

beta particles and gamma rays

alpha and beta particles

31 / 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

32 / 80

Category: CHEMISTRY PAST QUESTIONS

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

absorption

emission

combustion

diffusion

33 / 80

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

loss of heat to the surrounding

attainment of dynamic equilibrium

evolution of gas as it proceeds

positive change in value of enthalpy

34 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Catalyst

Reducing agent

Water

Freezing mixture

35 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Zinc and concentrated trioxonitrate (V) acid

Magnesium and dilute tetraoxosulphate (VI) acid

Copper and dilute hydrochloric acid

Water and calcium dicarbide

36 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Atomic radius

Electronegativity

Electon affinity

Ionization energy

37 / 80

Category: CHEMISTRY PAST QUESTIONS

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

temperature of the system

activation energy

degree of disorder in the system

number of molecules

38 / 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

39 / 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

6.35g

0.318g

18g

40 / 80

Category: CHEMISTRY PAST QUESTIONS

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

paramagnetism

nalleability

ductility

shiny appearance

41 / 80

Category: CHEMISTRY PAST QUESTIONS

Calcium atom ionizes by

gaining two electrons

sharing two electrons

gaining two protons

losing two electrons

42 / 80

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

HCI

Na+CI

NH4

CH4

43 / 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)

Dehydrating agent

Oxidising agent

Acid

Bleaching agent

44 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Group 111 A

Group V11 A

Group 1 A

Group 11 A

45 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Aluminium ions

Silver

Magnesium

Zinc ions

46 / 80

Category: CHEMISTRY PAST QUESTIONS

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

47 / 80

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

difference of 14 atomic mass units between successive members

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

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

48 / 80

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

ethanol

ammoniacal liquor

kerosene

paraffin oil

49 / 80

Category: CHEMISTRY PAST QUESTIONS

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

50 / 80

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

propan-1,2,3-triol

ethanal

ethanoic acid

ethene

51 / 80

Category: CHEMISTRY PAST QUESTIONS

Helium is preferred to hydrogen in filling balloons because hydrogen

is inflammable

is a component of water

exhibits isotopy

is diatomic

52 / 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 and lll only

l, ll, lll, and IV

l only

l and ll only

53 / 80

Category: CHEMISTRY PAST QUESTIONS

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

gas molecules colliding in a flask

planets going round the sun

wheelbarrow being pushed

car travelling on a straight line

54 / 80

Category: CHEMISTRY PAST QUESTIONS

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

evaporation

filtration

distillation

sublimation

55 / 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 pressure increased

the temperature is raised

the volume of the system is increased

56 / 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 concentration of ammonia will increase

the forward reaction will be favoured

Activation energy will decrease

57 / 80

Category: CHEMISTRY PAST QUESTIONS

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

free energy of the system

concentration of the reactants

temperature of the system

pressure applied to the system

58 / 80

Category: CHEMISTRY PAST QUESTIONS

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

100.0g

10.0g

40.0g

4.0g

59 / 80

Category: CHEMISTRY PAST QUESTIONS

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

ionic

dative

metallic

covalent

60 / 80

Category: CHEMISTRY PAST QUESTIONS

What is the shape of a molecule of CCI₄?

Linear

Tetrahedral

Pyramidal

Trigonal planar

61 / 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

62 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Glucose solution

Tetrachlormethane

Zinc rod

Hydrochloric acid

63 / 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 anode increases in mass

The blue colour of the solution fades gradually

The cathode becomes coated with copper

64 / 80

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is acidic

is a mixture

has pH value of 7

contains enzymes

65 / 80

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Sharing one electron

Gaining one electron

Losing one electron

Donating lone pair of electrons

66 / 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

monatomic ion is equal to its charge

element in the free state is zero

alkali meta like sodium in its compounds is + 1

67 / 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?

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?

R + P+ → P + R+

Q + S+ → S + Q+

S + P+ → P + S +

S + Q+ → Q + S+

69 / 80

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

concentrations of the products are greater than those of the reactants

concentrations of the reactants and products remain constant

reactants stop forming the products

reactants in the system are used up

70 / 80

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

under ultraviolet light

under paraffin oil

in a box lined with lead

in a cool, dark cupboard

71 / 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

72 / 80

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

magnetite

cassiterite

bauxite

cryolite

73 / 80

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

displacement reaction

decomposition

redox reaction

deliquescence

74 / 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?

Pressure has no effect on the equilibrium mixture

At equilibrium increase in temperature favours the reverse reaction

The forward reaction is exthermic

The reaction goes to completion at equilibrium

75 / 80

Category: CHEMISTRY PAST QUESTIONS

The crystal layers in graphite are held together by

electrostatic forces

van der Waals' forces

covalent bonds

hydrogen bonds

76 / 80

Category: CHEMISTRY PAST QUESTIONS

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

77 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Destructive distillation

Dehydration

Nutralization

Redox reaction

78 / 80

Category: CHEMISTRY PAST QUESTIONS

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

Propene

Benzene

Pentane

Hexane

79 / 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-

H+

CI-

Cu2+

80 / 80

Category: CHEMISTRY PAST QUESTIONS

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

NaI

NaBr

NaF

NaCI