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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.

46 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

46 questions

Question 1 of 20 46 total questions

Question 11

jamb 1995

In the industrial production of hydrogen from natural gas, carbon (IV) oxide produced along with the hydrogen is removed by?

Awashing with water under pressure

Bpassing the mixture into lime water

Cusing ammoniacal copper (l) chloride

Ddrying over phoshorus (V) oxide

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Question 12

jamb 1995

Which of the following equilibria is shifted to the right as a result of an increase in pressure?

AH_2(g) + I_2(g) 2HI_(g)

B2NO_2(g) N₂O_4(g)

CPCl_5(s) PCl_3(s) + Cl_2(g)

D2O_3(g) 3O_2(g)

View Explanation & Discuss

Question 13

jamb 1995

Which of the following processes leads to increase in entropy?

AMixing a sample of NaCl and sand

BCondensation of water vapour

CBoiling a sample of water

DCooling a saturated solution

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Question 14

jamb 1995

If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at?

Alow temperatures

Bhigh temperatures

Call temperatures

Dall pressures

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Question 15

jamb 1995

Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6l\(^-\)(aq) → 2Cr\(^{3+}\)(aq) + 3l(g) + 7H\(_2\)O(I).
The change in the oxidation number of oxygen in the equation above is?

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Question 16

jamb 1995

Which of the following is a redox reaction?

AKCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)

B2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)

C3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)

DH₂CO_3(aq) → H₂O_(I)2- + CO_2(g)

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Question 17

jamb 1995

2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is?

Aionization

Boxidation

Creduction

Drecombination

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Question 18

jamb 1995

How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulpohate (IV)?

(F = 96 500 C mol^-)

A0.5

B1.0

C1.5

D3.0

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Question 19

jamb 1995

In the process of silver-plating a metal M, the metal M is the?

Aanode and a direct current is used

Bcathode and an alternating current is used

Canode and an alternating current is used

Dcathode and a direct current is used

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Question 20

jamb 1995

Neutralization involves a reaction between H₃O⁺ and?

ACI^-

BOH^-

CNO₃^-

DCO₃^2-

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Question 21

jamb 1995

In general, an increase in temperature increases the solubility of a solute in water because?

Amore solute molecules collide with each other

Bmost solutes dissolve with the evoltion of heat

Cmore solute molecules dissociate at hihger temperatures

Dmost solutes dissolve with absorption of heat

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Question 22

jamb 1995

The difference between colloides and and suspensions is brought out clearly by the fact that while colloids?

Ado not scatter light, suspensions do

Bcan be separated by filtration, suspension cannot be so separated

Ccan be separated by a membrane, suspensions cannot

Ddo not settle out on standing, suspensions do

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Question 23

jamb 1995

When plastics and packaging materials made from chloroethene are burnt in the open, the mixture of gases released into the atmosphere is most likely to contain?

Aethane

Bchlorine

Chydrogen chloride

Dethene

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Question 24

jamb 1995

Deliquescent substances are also?

Aefflorescent

Banhydrous

Chygroscopic

Dinsoluble

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Question 25

jamb 1995

Helium is often used in observation balloons because it is?

Alight and combustible

Blight and non-combustible

Cheavy and combustible

Dheavy and non-combustible

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Question 26

jamb 1995

Which of the following statements is FALSE about isotopes of the same element?

AThey have the same number of electrons in their outermost shells

BThey have different atomic masses

CThey have the same atomic number and the number of electrons

DThey have the same atomic number but different number of electrons

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Question 27

jamb 1995

The ability of ionic solids is generally due to the?

Anegative electron affinity of most atoms

Bcrystal lattice forces

Celectron pair sharing

Dpositive ionization potentials

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Question 28

jamb 1995

In the oil drop experiment, Millikan determined the?

Acharge to mass ratio of the electron

Bmass of the electron

Ccharge of the electron

Dmass of the proton

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Question 29

jamb 1995

A particle that contains 8 proton, 9 neutrons and 7 electrons could be written as?

BO⁺

DO^-

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Question 30

jamb 1995

A liquid begins to boil when?

Aits vapour pressure is equal to the vapour pressure of its solid at the given temperature

Bmolecules start escaping from its surface

Cits vapour pressure equals the atmosphere pressure

Dits volume is sightly increased

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