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Chemistry Past Questions

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87 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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87 questions

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Question 31

jamb 1992

For a general equation of the nature xP + yQ ≈ mR + nS, the expression for the equilibrium constant is?

Ak (p)^x (Q)^y

B(p)^x (Q)^y / (R)^m (S)ⁿ

C(R)^m (S)ⁿ / (p)^x (Q)^y

Dm(R) n (S) / x(P) y (Q)

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Question 32

jamb 1992

Which of the following equilibria shows little or no net reaction when the volume of the system is decreased?

AH₂_(g) + I₂_(g) ≈ 2HI_(g)

B2NO₂^(g) ≈ N₂O₄_(g)+O₄_(g)N₂O₄_(g)

CPCI₅_(g) ≈ PCI₃_(g) + CI₂_(g)

DZnO_(s) + CO₂_(g) ≈ ZnCO₃_(g)

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Question 33

jamb 1992

In what way is equilibrium constant for the forward reaction related to that of the reversed reaction?

AThe additional of the two is expected to be one

BThe product of the two is expected to be one

CThe two equilibrium constants are identical

DThe product of the two is always greater than one

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Question 34

jamb 1992

In which of the following is the entropy change positive?

AH₂O_(I) → H₂O_(g)

BCu²⁺_(aq) + Fe_(s) → Fe²⁺_(aq) + Cu_(s)

CN₂_(g) + 3H₂_(g) → 2NH₃_(g)

D2HCI_(g) → H₂_(g) + CI₂_(g)

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Question 35

jamb 1992

\(MnO_2 + 2CI^- + 4H^+ → Mn^{2+} + CI_2 + 2H_2O\).
The changes in oxidation numbers when the manganese, chloride, and hydrogen ions react according to the above equation are respectively?

A2, 2, 4

B-1, -2, 4

C-2, 1, 0

D2, 4, 0

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Question 36

jamb 1992

S₂O^2-₃ + I₂ → S₂O₆^2- + 2I^-. In reaction above, the oxidizing agent is?

AS₂O₃^2-

BI₂

CS₄O₆^2-

DI^-

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Question 37

jamb 1992

Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes.

A2.7

B5.4

C10.8

D21.7

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Question 38

jamb 1992

Copper (II) tetraoxosulphate (VI) solution is electrolyzed using carbon electrodes. Which of the following are produced at the anode and cathode respectively ?

ACopper and oxygen

BOxygen and copper

CHydrogen and copper

DCopper and hydrogen

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Question 39

jamb 1992

How many grams of H₂SO₄ are necessary for the preparation of 0.175 dm³ of M 6.00 M H₂SO₄?

(S = 32.06, O = 16.00 H = 1.00)

A206.0 g

B103.0 g

C98.1 g

D51.5 g

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Question 40

jamb 1992

Arrange HCI, CH₃COOH, C₆H₅CH₃ in order of increasing conductivity.

AHCI, CH₃COOH, C₆H₅CH₃

BC₆H₅CH₃, HCI, CH₃COOH

CC₆H₅CH₃, CH₃COOH, HCI

DCH₃COOH, C₆H₅CH₃, HCI

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Question 41

jamb 1992

A sample of orange juice is found to have a pH of 3.80. What is he concentration of the hydroxide ion in the juice?

A1.6 x 10^-4

B6.3 x 10^-11

C6.3 x 10^-4

D1.6 x 10^-11

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Question 42

jamb 1992

An emulsion paint consists of ?

Agas or liquid particles dispersed in liguid

Bliquid particles dispersed in liquid

Csolid particles dispersed in liquid

Dsolid particles dispersed in solid

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Question 43

jamb 1992

On which of the following is the solubility of a gaseous substance dependent? I. Nature of solvent II. Nature of solute III. Temperature IV. Pressure

AI, II, III and IV

BI and II only

CII only

DI, III and IV only

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Question 44

jamb 1992

Water for town supply is chlorinated to make it free from?

Abad odour

Bbacteria

Ctemporary hardness

Dpermanent hardness

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Question 45

jamb 1992

Which of the following gases dissolves in water vapour to produce acid rain during rainfall?

AOxygen

BCarbon (II) oxide

CNitrogen

DSulphur (IV) oxide

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Question 46

jamb 1992

Four elements P,Q,R and S have 1,2,3, and 7 electrons in their outermost shells respectively. The element which is unlikely to be a metal is?

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Question 47

jamb 1992

The pollutants that are likely to be present in an industrial environment are?

AH₂S,SO₂ and oxides of nitrogen

BNH₃, HCI and CO

CCO₂, NH₃ and H₂S

Ddust, NO and CI₂

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Question 48

jamb 1992

¹⁴₇N + X → ¹⁷₈O + ¹₁ H. In the above reaction, X is a?

Aneutron

Bhelium atom

Clitgium atom

Ddeuterium atom

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Question 49

jamb 1992

How many lone pairs of electron are there on the central atom of the H2O molecules?

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Question 50

jamb 1992

The nucleus of the isotope tritium, contains?

Atwo neutrons with no protons

Bone neutron and one protons

Ctwo neutrons and one proton

Dtwo neutrons, one proton and one electron

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