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SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS)

CHEMISTRY PAST QUESTIONS

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1 / 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 pressure increased

a catalysty is intoduced into the system

the temperature is raised

the volume of the system is increased

2 / 60

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 cathode becomes coated with copper

The blue colour of the solution fades gradually

Both electrodes gain electrons

3 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Silver

Aluminium ions

Zinc ions

Magnesium

4 / 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 concentration of ammonia will increase

Activation energy will decrease

the reaction will go to completion

the forward reaction will be favoured

5 / 60

Category: CHEMISTRY PAST QUESTIONS

Pauli Exclusion Principle is related to

quantum numbers of electrons

reversiblility of equlibrium reactions

electronegativity values of elements

collision theory of reaction rates

6 / 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

alpha particles and gamma rays

alpha and beta particles

beta particles and gamma rays

alpha particles only

7 / 60

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

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

difference of +1 in the oxidation numbers of successive members

8 / 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

9 / 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

protective oxide coating

different chemical properties

higher molar mass

smaller surface area

10 / 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

11 / 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

activation energy is high and a catalyst is required

the reaction is endothermic and occurs at high temperature

direct combination is involved and the reaction is endothermic

a solid is formed and heat is evolved

12 / 60

Category: CHEMISTRY PAST QUESTIONS

It can be concluded that gastric juice

is acidic

has pH value of 7

contains enzymes

is a mixture

13 / 60

Category: CHEMISTRY PAST QUESTIONS

Aluminium is extracted from

bauxite

cassiterite

magnetite

cryolite

14 / 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?

Q + S+ → S + Q+

S + Q+ → Q + S+

S + P+ → P + S +

R + P+ → P + R+

15 / 60

Category: CHEMISTRY PAST QUESTIONS

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

diffusion

combustion

emission

absorption

16 / 60

Category: CHEMISTRY PAST QUESTIONS

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

carbon (IV) oxide

hydrogen

oxygen

sulphur (VI) oxide

17 / 60

Category: CHEMISTRY PAST QUESTIONS

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

insolube

hydrated

anhydrous

hygroscopic

18 / 60

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

19 / 60

Category: CHEMISTRY PAST QUESTIONS

The liquid product of the destructive distillation of coal is

kerosene

paraffin oil

ethanol

ammoniacal liquor

20 / 60

Category: CHEMISTRY PAST QUESTIONS

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

NaI

NaF

NaCI

NaBr

21 / 60

Category: CHEMISTRY PAST QUESTIONS

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

covalent

metallic

dative

ionic

22 / 60

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

activation energy

number of molecules

23 / 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)

Dehydrating agent

Acid

Bleaching agent

Oxidising agent

24 / 60

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

dative

ionic

25 / 60

Category: CHEMISTRY PAST QUESTIONS

Gas molecules are said to be perfectly elastic because

they collide without loss of energy

they move about in straight lines

the volume occupied by them is negligible

the distances between them are negligible

26 / 60

Category: CHEMISTRY PAST QUESTIONS

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

4.0g

40.0g

100.0g

10.0g

27 / 60

Category: CHEMISTRY PAST QUESTIONS

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

28 / 60

Category: CHEMISTRY PAST QUESTIONS

Metals are said to be malleable because they

are good conductors heat

are good conductors of electricity

can be beaten into sheets

can be alloyed

29 / 60

Category: CHEMISTRY PAST QUESTIONS

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

mass

density

number of molecules

rate of diffusion

30 / 60

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 is more stable than Q

S decays faster than Q

Q emits fewer particles than S

31 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Chlorine

Nitrogen

Carbon

Sulphur

32 / 60

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

33 / 60

Category: CHEMISTRY PAST QUESTIONS

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

The anode increases in mass

Both electrodes gain electrons

The blue colour of the solution fades gradually

The cathode becomes coated with copper

34 / 60

Category: CHEMISTRY PAST QUESTIONS

Dehydration of ethanol produces

ethanoic acid

ethanal

propan-1,2,3-triol

ethene

35 / 60

Category: CHEMISTRY PAST QUESTIONS

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

a strong electrolyte

ionic

deliquescent

a normal salt

36 / 60

Category: CHEMISTRY PAST QUESTIONS

Chlorine atom forms CI by

Donating lone pair of electrons

Losing one electron

Sharing one electron

Gaining one electron

37 / 60

Category: CHEMISTRY PAST QUESTIONS

The crystal layers in graphite are held together by

covalent bonds

hydrogen bonds

van der Waals' forces

electrostatic forces

38 / 60

Category: CHEMISTRY PAST QUESTIONS

An exothermic reaction is one which involves

loss of heat to the surrounding

positive change in value of enthalpy

attainment of dynamic equilibrium

evolution of gas as it proceeds

39 / 60

Category: CHEMISTRY PAST QUESTIONS

Rusting of iron is an example of

redox reaction

displacement reaction

deliquescence

decomposition

40 / 60

Category: CHEMISTRY PAST QUESTIONS

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

41 / 60

Category: CHEMISTRY PAST QUESTIONS

A radioactive solid is best stored

in a cool, dark cupboard

under paraffin oil

under ultraviolet light

in a box lined with lead

42 / 60

Category: CHEMISTRY PAST QUESTIONS

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

car travelling on a straight line

gas molecules colliding in a flask

wheelbarrow being pushed

planets going round the sun

43 / 60

Category: CHEMISTRY PAST QUESTIONS

Petrol consists mainly of

hydrocarbons

alkanoates

alktanols

polymers

44 / 60

Category: CHEMISTRY PAST QUESTIONS

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

evaporation

sublimation

distillation

filtration

45 / 60

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

46 / 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

Graham's law

Dalton's law

Gay-Lussac's Law

47 / 60

Category: CHEMISTRY PAST QUESTIONS

Which of the following contains co-ordinate covalent bond?

Na+CI

HCI

CH4

NH4

48 / 60

Category: CHEMISTRY PAST QUESTIONS

Chemical equilibrium is attained when

reactants in the system are used up

reactants stop forming the products

concentrations of the reactants and products remain constant

concentrations of the products are greater than those of the reactants

49 / 60

Category: CHEMISTRY PAST QUESTIONS

When alkanols react with sodium, the ga evolved is

methane

oxygen

ethyne

hydrogen

50 / 60

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

51 / 60

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]

101

122

52 / 60

Category: CHEMISTRY PAST QUESTIONS

Pipe-borne water is usually chlorinated in order to

coagulate sediments in the water

remove the hardness in the water clear

kill harmful bacteria in the water

improve the teste of the water

53 / 60

Category: CHEMISTRY PAST QUESTIONS

Electrovalent compounds are characterized by

strong oxidizing ability

high molar mass

solubility in ethanol

high melting point

54 / 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)

Ammonium chloride

Sodium tetraoxosulphate (VI)

55 / 60

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 forward reaction is exthermic

At equilibrium increase in temperature favours the reverse reaction

Pressure has no effect on the equilibrium mixture

The reaction goes to completion at equilibrium

56 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Copper alloy

Copper (ll) oxide

Copper (ll) trioxocarbonate (IV)

Copper turnings

57 / 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?

58 / 60

Category: CHEMISTRY PAST QUESTIONS

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

59 / 60

Category: CHEMISTRY PAST QUESTIONS

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

Copper

Oxygen

Nitrogen

Hydrogen

60 / 60

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

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