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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

waec 2022

If 50 cm\(^{3}\) of a saturated solution of KNO\(_{3}\) at 40 °C contained 5.05 g of the salt, its solubility at the same temperature would be
[KNO\(_{3}\) = 101]

A1.0 mol dm\(^{-3}\)

B1.5 mol dm\(^{-3}\)

C2.0 mol dm\(^{-3}\)

D5.0 mol dm\(^{-3}\)

View Explanation & Discuss

Question 12

waec 2022

What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm\(^{3}\) cylinder?
[R=0.082 atm dm\(^{-3}\) mol\(^{-1}\) K\(^{-1}\)]

A0.32

B1.52

C3.13

D31.25

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Question 13

waec 2022

A hydrogen chloride gas reacted with oxygen gas to yield water and chlorine gas. The mole ratio of the hydrogen chloride gas to water is

A1:3

B2:1

C3:1

D4:1

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Question 14

waec 2022

Which of the following statements about liquids is/are true?

I. Liquids maintain their volume at constant temperature.
II. Liquids have fixed shape
III. Liquids do not diffuse
IV. Change in pressure affects volume of liquids

AI only

BIV only

CI and IV only

DII and III only

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Question 15

waec 2022

When air in a syringe is compressed such that there is no change in temperature, the

Aair liquefies

Bpressure increases

Cintermolecular space increases

Ddensity decreases

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Question 16

waec 2022

Consider the following reaction equation
N\(_{2}\)(g) + 3H\(_{2(g)}\) ⇌ 2NH3(g) ∆H = -92kJ

Increasing the temperature of the reaction would

Ashift the equilibrium to the right

Bincrease the yield of ammonia

Cdecrease the amount of hydrogen

Ddecrease the yield of ammonia

View Explanation & Discuss

Question 17

waec 2022

Which of the following statements about an equilibrium system is correct?

AForward and backward reactions occur
at the same rate

BThe concentrations of reactants must
equal that of the products

CThe concentrations of, reactants and products can be changed by adding a catalyst,

DThe concentrations of reactants and
products are not affected by a change in temperature

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Question 18

waec 2022

Which of the following gases is alkaline?

ANO\(_{2}\)

BCO\(_{2}\)

CNH\(_{3}\)

DN\(_{2}\)O

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Question 19

waec 2022

Graphite is used as a dry lubricant due to the presence of

Amobile electrons

Bfree electrons

Coctahedral structures

Dlayered structures

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Question 20

waec 2022

What is the partial pressure of oxygen at s.t.p. in a gaseous mixture containing 100 cm3 of oxygen and 900 cm3 of nitrogen gas?

A1.0 atm

B0.1 atm

C9.0 atm

D0.9 atm

View Explanation & Discuss

Question 21

waec 2022

Which of the following acids would form normal salt only?

ATetraoxosulphate(VI) acid

BTrioxonitrate(V) acid

CTetraoxophosphate(V) acid

DTrioxosulphate(IV) acid

View Explanation & Discuss

Question 22

waec 2022

Consider the following reaction equation:
CaO + SiO\(_{2}\) ------> CaSiO\(_{3}\)
Silicon(IV) oxide is acting as

Aa basic oxide

Ba reducing agent

Can acidic oxide

Dan oxidizing agent

View Explanation & Discuss

Question 23

waec 2022

Before a reaction could take place, there should be

Aionization of reactant particles

Bbreakage of bonds of products

Cionization of product particles

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Question 24

waec 2022

A white precipitate was formed when BaCl\(_{2(aq)}\) was added to an aqueous solution
of a salt X. The precipitate dissolved in dilute HCl with rapid effervescence. Salt X is likely to contain

ASO\(_{4}\) \(^{2-}\) ions

BSO\(_{3}\) \(^{2-}\) ions

CNO\(_{3}\)- ions

DCO\(_{3}\) \(^{2-}\)- ions

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Question 25

waec 2022

Increasing the temperature generally

Adecreases the solubility of a solid in a liquid but increases the solubility of a gas in a liquid.

Bincreases the solubility of a solid in a liquid but decreases the solubility of a gas in a liquid.

Cincreases the solubility of both a solid and a gas in a liquid

Ddecreases the solubility of both a solid and a gas in a liquid

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Question 26

waec 2022

If 5.0 g of marble reacts with 25.0 cm3 hydrochloric acid, which of the following combinations has the fastest reaction rate?

AMarble chips and 2.0 mol dm\(^{-3}\) HCl\(_{(aq)}\)

BMarble chips and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)

CPowdered marble and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)

DPowdered marble and 2.0 mol dm\(^{-3}\) HCl\(_{(aq)}\)

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Question 27

waec 2022

A colourless gas with a pungent smell is evolved when dilute hydrochloric acid is added to a sample of a salt. The gas evolved could turn

Aacidified K\(_{2}\)Cr\(_{2}\)O\(_{7}\) solution colourless

Bacidified KMnO\(_{4}\) solution colourless

CFe(NO\(_{3}\))\(_{2}\) solution green

DPb(NO\(_{3}\))\(_{2}\) paper black

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Question 28

waec 2022

The IUPAC name for CH\(_{3}\)CHCH\(_{3}\)CHCLCHCH\(_{3}\)CH\(_{2}\)CH\(_{3}\) is

A2, 4 - dimethyl - 3 - chlorohexane

B3, 5 - dimethyl - 4 - chlorohexane

C4 - chloro - 3, 5 - dirnethylhexane

D3 - chloro - 2, 4 - dimethylhexane

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Question 29

waec 2022

Oxochlorate(I) acid is used as a bleaching agent because it is

Aa weak acid

Ba reducing agent.

Can oxidizing agent

Da strong acid.

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Question 30

waec 2022

Determine the quantity of electricity used when a current of 0.20 amperes is passed through an electrolytic cell for 60 minutes.

A12C

B120C

C360C

D720C

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