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Chemistry Past Questions

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52 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

52 questions

Question 1 of 20 52 total questions

Question 11

waec 2002

What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)

A\(\frac{[NO^2]}{[N^2] + [O^2]}\)

B\(\frac{[2NO]^2}{[N_2][O_2]}\)

C\(\frac{[N_2] + [O_2]}{2[NO]^2}\)

D\(\frac{[NO]^2}{[N_2][O_2]}\)

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Question 12

waec 2002

What will happen if more heat is applied to the following system at equilibrium?

X\(_2\)(g) + 3Y\(_2\)(g) ⇌ 2XY\(_3\)(g); ∆H = xKJmol\(^{-1}\)

Athe yield of XY ₃ will decompose

Bmore of XY₃ will decompose

CMore of X₂ will react

Dthe forward reaction will remain static

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Question 13

waec 2002

Which of the following salt solutions will have a pH greater than 7?

ANaCI_(aq)

BNa₂CO_3(aq)

CNa₂SO_4(aq)

DNaHSO_4(aq)

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Question 14

waec 2002

Calculate the mass of sodium hydroxide in 5.00 dm³ of a 0.125 mol dm^-3 solution. [NaOH = 40 g mol^-1]

A0.0156 g

B0.625 g

C1.00 g

D25.0 g

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Question 15

waec 2002

Which of the following substances increases in mass when heated in air?

ASodium chloride

Blodine crystals

CMagnesium ribbon

DCopper (ll) oxide

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Question 16

waec 2002

A substance is said to be hygroscopic if it absorbs

Awater from the atmosphere to form a solution

Bheat from the surrounding

Ccarbon (IV) oxide from the atmosphere

Dmoisture from the atmosphere without dissolving

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Question 17

waec 2002

Which of following acids forms normal salts only?

ATetraoxosulphate (VI) acid

BTrioxosulphate (IV) acid

CAcetic acid

DTetraoxophosphate (V) acid

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Question 18

waec 2002

A major factor considered in selecting a suitable method for preparing a simple salt is its

Acrystalline form

Bmelting point

Creactivity with dilute acids

Dsolubility in water

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Question 19

waec 2002

The gas given off when NH4 Cl is heated with an alkali is

AH₂

BCl₂

CN₂

DNH₃

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Question 20

waec 2002

Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]

A123g

B139g

C155g

D182g

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Question 21

waec 2002

Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]

A1.80g

B3.55g

C7.10g

D15.50g

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Question 22

waec 2002

What volume of hydrogen will be produced if 100cm³ of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH_3(g) → N_2(g) + 3H_2(g)

A50cm³

B150cm³

C200cm³

D300cm³

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Question 23

waec 2002

Which of the following decreases when a given mass of gas is compressed to half its initial volume?

AAverage intermolecular distance

BFrequency of collisions

CNumber of molecules present

DAtomic radius of each particle

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Question 24

waec 2002

If a metal R forms a compound with the formula R(NO₃)² , the formula of its tetraoxosulphate (IV) is

AR(SO₄)₂

BRSO₄

CR₂SO₄

DR₂(SO₄)₃

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Question 25

waec 2002

An element Y has the electronic configuration 1s²2s²2p⁶6²3p₄. To what period does it belong in the periodic table?

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Question 26

waec 2002

The conclusion from Rutherford's alpha-scattering experiment is that

Aatoms are mostly empty space with a small nucleus

Bemissions from radioactive substances consist of three main components

Cthere is nuclear pull on orbital electrons

Delectrons are deflected by both magnetic and electric fields

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Question 27

waec 2002

Which of the following elements has a ground state electronic configuration with an incomplete penultimate shell?

AIron

BSodium

CAluminium

DCalcium

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Question 28

waec 2002

A hydrogen atom which has lost an electron contains

Aone proton only

Bone neutron only

Cone proton and one neutron

Done proton, one electronic and one neutron

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Question 29

waec 2002

The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?

A16

B17

C18

D19

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Question 30

waec 2002

The atom of an element X is represented as \(^y_z X\). The basic chemical properties of X depend on the value of

CY - Z

DZ - Y

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