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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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2,505 questions

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Question 721

jamb 2001

2SO\(_2\)(g) + O\(_2\)(g) ↔ 2SO\(_3\)(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?

Adecreasing the temperature of the system

Bdecrease the pressure of the system

CThe addition of a catalyst to the system

DIncreasing the surface area of the vessel

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Question 722

jamb 2001

C(s) + 2S(g) → CS\(_2\)(g)
ΔH = +89 kJ mol-1
The chemical equation above implies that

Aeach of carbon and sulphur has 89 kJ of energy

Bboth carbon and sulphur contribute 89 kJ of energy

C89 kJ of energy is released

D89 kJ of energy is absorbed

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Question 723

jamb 2001

Ethanoic acid is

Atribasic

Bunionizeable

Cmonobasic

Ddibasic

View Explanation & Discuss

Question 724

jamb 2001

What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]

A32

D16

View Explanation & Discuss

Question 725

jamb 2001

Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises?

AThe bonds in the reacting molecules are more readily broken

BThe molecular collisions become more violent

CA lower proportion of the molecules has the necessary minimum energy to react

DThe collision frequency of the molecules increase

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Question 726

jamb 2001

A metal M displaces zinc from zinc chloride solution. This shows that

AM is more electronegative than zinc

BZinc is above hydrogen in the series

CM is more electropositive than zinc

DElectrons flow from zinc to M

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Question 727

jamb 2001

P(g) + Q(g) ↔ 3R(s) + S(g) ΔH is negative
Which of the following will increase the yield of R?

AUsing a larger close vessel

BIncreasing the temperature

CRemoving some S

DAdding a positive catalyst

View Explanation & Discuss

Question 728

jamb 2001

In which of the following reactions does reduction takes place

AFe²⁺ - e^- → Fe³⁺

B2O^2- →O₂ + 4e^-

CCr – 2e^- → Cr²⁺

D2H⁺ + 2e^- → H₂

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Question 729

jamb 2001

Phosphorus is stored under water to prevent it from

ADehydrating

BBecoming inert

CSmelling

DCatching fire

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Question 730

jamb 2001

The chemical used for coagulation in water purification is

AAluminium tetraoxosulphate (VI)

BCopper tetraoxosulphate (VI)

CSodium tetraoxosulphate (VI)

DCalcium tetraoxosulphate (VI)

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Question 731

jamb 2001

Environmental pollution is worsened by the release from automobile exhausts of?

AWater vapour

BSteam

CSmoke

DHeavy metals

View Explanation & Discuss

Question 732

jamb 2001

What is the decrease in volume of air when pyrogallol is shaken with 30.00cm\(^3\) of air ?

A15.00cm³

B6.30cm³

C0.63cm³

D0.06cm³

View Explanation & Discuss

Question 733

jamb 2001

Pure solvents are obtained by

ADistillation

BCondensation

CExtraction

DEvaporation

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Question 734

jamb 2001

Deliquescent substances are used for

ACooling

BWetting

CMelting

DDrying

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Question 735

jamb 2001

The pollution from petroleum spillage in rivers and lakes can best be dispersed by

APouring detergents

BPassing of ships through the area

CPouring organic solvents

DEvaporation

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Question 736

jamb 2001

Which of the following statements is correct about the average kinetic energy of the molecules of a gas?

AIt increase with increase in pressure

BIt increase at constant temperature

CIt increase with increase in temperature

DIt increase with increase in volume

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Question 737

jamb 2001

An element X with relative atomic mass 16.2 contains two isotopes \(^{16}_{8}\)X with relative abundance of 90% and \(^{m}_{8}\)X with relative abundance of 10%. The value of m is

A16

B18

C12

D14

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Question 738

jamb 2001

Four elements W, X, Y and Z have atomic number 2,6,16 and 20 respectively. Which of these elements is a metal?

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Question 739

jamb 2001

Millikan's contributions to the development of atomic theory is the determination of

Acharge on electron

Bpositive rays

Ccharge to mass ratio

Dcathode rays

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Question 740

jamb 2001

An oxide XO\(_2\) has a vapour density of 32. What is the atomic mass of X?

A32

B20

C14

D12

View Explanation & Discuss

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