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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.

77 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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77 questions

Question 1 of 20 77 total questions

Question 21

jamb 2006

H\(_2\)(g) + Br\(_2\)(g) → 2HBr(g)
The above reaction is carried out at 25\(^0\)C. ΔH is -72 kJ mol-1 and ΔS is - 106 J mol-1K-1, the reaction will?

Anot proceed spontaneously at the given

Bproceed spontaneously at the given temperature

Cproceed in the reverse direction at the given temperature

Dproceed spontenously at lower temperature

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Question 22

jamb 2006

The ion that can be used as an oxidizing agent is

AAu³⁺

BFe³⁺

CClO^-

DCa²⁺

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Question 23

jamb 2006

2C\(_2\)H\(_2\)(g) + 5O\(_2\)(g) → 4CO\(_2\)(g) + 2H\(_2\)O(g)
In the reaction above, the mass of carbon(IV)oxide produced on burning 78 g of ethyne is
[C =12, O = 16, H = 1]

A264 g

B39 g

C352 g

D156 g

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Question 24

jamb 2006

If 30cm\(^3\) of gas at 50\(^0\)C is warmed to 80\(^0\)C at a fixed pressure, the fractional increase in volume is

A0.009

B0.093

C0.910

D1.090

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Question 25

jamb 2006

The idea of planetary electron was that of

ARutherford

BThompson

CBohr

DDalton

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Question 26

jamb 2006

The order in which a mixture of sand, ammonium chloride and sodium chloride can be separated is

Adissolution → dryness → filtration → evaporation

Bfiltration → sublimation → evaporation → dryness

Csublimation → dissolution → filtration → evaporation

Ddissolution → filtration → sublimation → evaporation

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Question 27

jamb 2006

A decrease in atomic size and an increase in nuclear charge across a period lead to

Aan increase in the tendency to lose electron

Ban increase in chemical reactivity

Ca decrease in electropositivity

Da decrease in covalency in bond formation

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Question 28

jamb 2006

The element with the electron configuration 1S\(^2\)2S\(^2\)2P\(^3\) is

Acalcium

Bchlorine

Coxygen

Dnitrogen

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Question 29

jamb 2006

What is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?

A62.5 g

B40.0 g

C6.3 g

D2.5 g

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Question 30

jamb 2006

Nuclear fission involves the splitting of a heavy element into two nuclei of

Anearly equal masses with a release of energy and radiation

Bequal masses with a release of energy

Cequal masses with a release of energy and radiation

Dunequal masses without any release of energy

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Question 31

jamb 2006

The volume of 2.5 moles of oxygen at s.t.p is
[Molar volume of a gas at s.t.p = 22.4 dm³]

A50.0 dm³

B84.0 dm³

C28.0 dm³

D56.0 dm³

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Question 32

jamb 2006

A difference between chemical and physical change is that in a chemical change

Aoxygen is consumed

Bheat is supplied

Ca reversible process oocurs

Da new substance is formed

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Question 33

jamb 2006

A particle that contains 11 protons, 12 neutrons and 10 electrons is probably a

Aneutral non-metal

Bmetallic ion

Cnon-metallic ion

Dneutral metal

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Question 34

jamb 2006

When a crystal was added to the clear solution of its salt, the crystal did not dissolve and the solution remained unchanged. This showed that the solution was

Asupersaturated

Bconcentrated

Cunsaturated

Dsaturated

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Question 35

jamb 2006

Water has the ability to dissolve almost all substance because its molecules has a structure with

Aone positive end and one neutral end

Bone positive end and one negative end

Ctwo negative ends

Dtwo positive ends

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Question 36

jamb 2006

Which of the following results in the fall of acid rain?

AOxides of lead

BParticulate matter

COxides of sulphur

DGaseous hydrocarbon

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Question 37

jamb 2006

When 50cm\(^3\) of a saturated solution of sugar of molar mass 342 g at 40\(^o\)C was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40\(^o\)C is

A2.0 mol dm^-3

B3.5 mol dm^-3

C7.0 mol dm^-3

D10.0 mol dm^-3

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Question 38

jamb 2006

The products of the combustion of candle wax are?

Ahydrogen and water

Boxygen and water

Ccarbon (IV) oxide and water

Dcarbon (II) oxide and water

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Question 39

jamb 2006

An emulsion may be produced by shaking a detergent solution with

Apalm wine

Bethanoic acid

Cpalm oil

Dwater

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Question 40

jamb 2006

One mole of a hydrocarbon contains 36g of carbon and its vapour density is 20. The structure of the hydrocarbon is

ACH₃C ≡ CH

BCH₃CH = CH₂

CCH₃CH₂C ≡ CH

DCH₃CH₂ CH₃

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