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Chemistry Past Questions

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50 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

50 questions

Question 1 of 20 50 total questions

Question 11

jamb 1992

Which of the following oxides of nitrogen is unstable in air?

ANO₂

BNO

CN₂O₄

DN₂O_5-

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Question 12

jamb 1992

Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen.

Ai and ii

Bii and iv

Ci and iii

Dii and iv

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Question 13

jamb 1992

Which of these statements is TRUE about carbon (IV) oxide?

Ait supports combustion

BIt is strongly acidic in water

CIt is very soluble in water

DIt supports the buring of magnesium to produce magnesium oxide

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Question 14

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 15

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 16

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 17

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 18

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 19

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 20

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 21

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 22

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 23

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 24

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 25

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 26

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 27

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 28

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 29

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 30

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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