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Chemistry Past Questions

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143 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

143 questions

Question 1 of 20 143 total questions

Question 31

waec 2001

If 10 cm 3 of distilled water is added to 10 cm3 of an aqueous salt solution, the concentration of the solution

Aincreases

Bdecreases

Cremains constant

Ddoubles

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Question 32

waec 2001

Sugars can be hydrolyzed at room temperature by the action of

Amineral acids

Bstrong bases

Cenzymes

Doxidants

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Question 33

waec 2001

Which of the following constitutes an advantage in the use of hard water?

AFormation of scum with soap

BFurring of kettles

CBlockage of water pipes

DFormation of strong bones

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Question 34

waec 2001

What is the function of H2SO4 in the following reaction?

C12H22O11 conc. H2SO4 → 12C + 11H2O

AOxidizing agent

BStrong acid

CDehydrating agent

DCatalyst

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Question 35

waec 2001

Which of the following polymers contains nitrogen?

ANylon

BPolyvinyl chloride

CPolyethene

DCellulose

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Question 36

waec 2001

One of the products of combustion of pentane in excess air is

Apentanol

Bpentene

Cnitrogen (ll) oxide

Dcarbon (IV) oxide

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Question 37

waec 2001

Benzene produces more soot than ethene on burning because benzene

Ahas a higher molar mass

Bhas a higher degree of unsaturation

Cundergoes substitution and addition reactions

Dis a liquid at room temperature

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Question 38

waec 2001

Hydrogenation of butene yields

Abutyne

Bbutane

Cpentence

Dbutanol

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Question 39

waec 2001

A feasible cell was constructed by joining the two half cells below. Cu\(^{2+}\) (aq) + 2e\(^-\) → Cu(s) E\(^0\) = +0.34 V; Zn\({^2+}\) + 2e\(^-\) → Zn\((_s)\) E\(^0\) = - 0.76V. What is the standard e.m.f. of the cell?

A- 1.1V

B- 0.42V

C+0.42V

D+1.1V

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Question 40

waec 2001

In the electrolysis of CuSO4(aq) using copper electrodes, the reaction at the anode is

Adischarge of SO₄ ^2-

Bdischarge of OH^-

Cdissolution of copper electrode

Devolution of oxygen

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Question 41

waec 2001

Given that the order of reactivity of four metals is P>Q>R>S, which of the following reactions is feasible?

AS + P⁺ → P + S ⁺

BQ + S⁺ → S + Q⁺

CR + P⁺ → P + R⁺

DS + Q⁺ → Q + S⁺

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Question 42

waec 2001

A concentrated solution containing H+, Cu2+,OH- and CI- was electrolyzed using platinum electrodes which of the ions will be discharged at the cathode?

AH⁺

BCu²⁺

COH^-

DCI^-

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Question 43

waec 2001

Which of the following substances decomposes when an electric current is passed through it?

AGlucose solution

BZinc rod

CHydrochloric acid

DTetrachloromethane

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Question 44

waec 2001

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

AOxygen

BHydrogen

CNitrogen

DCopper

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Question 45

waec 2001

What is the oxidation number of nitrogen in Al(NO\(_3\))\(_3\)?

A+ 1

B+ 3

C+ 5

D+ 6

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Question 46

waec 2001

A reaction is represented by the equation below. A2(g) + B2(g) → 2AB(g); ∆H = +X kJmol-1 Which of the following statements about the system is correct?

AThe reaction goes to completion at equilibrium

BThe forward reaction is exothermic

CAt equilibrium increase in temperature favours the reverse reaction

DPressure has no effect on the equilibrium mixture

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Question 47

waec 2001

Consider the following equation: Ag+ (aq) + CI-(aq) → Ag+CI- (s) ; ∆H = - 65.7 kJmol-1. From the equation, it can be deduced that

Adirect combination is involved and the reaction is endothermic

Ba solid is formed and heat is evolved

Cactivation energy is high and a catalyst is required

Dthe reaction is endothermic and occurs at high temperature

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Question 48

waec 2001

What does ∆H represent in the following equation ? Cl(g) + e- → CI- (g); ∆H = - 363 kJ mol-1

Alonization energy

BElectron affinity

CDissociation energy

DHeat of atomization

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Question 49

waec 2001

It can be concluded that gastric juice

Acontains enzymes

Bis acidic

Cis a mixture

Dhas pH value of 7

View Explanation & Discuss

Question 50

waec 2001

A gas was evolved when a sample of gastric juice reacted with sodium trioxocarbonate (IV) . The gas evolved was

ANH₃

BSO₂

CHCI

DCO₂

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