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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.

49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

49 questions

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Question 21

jamb 1991

Atoms of element X (with 2 electrons in the outer shell). combine with atoms of Y (with 7 electrons in the outer shell). Which of the following statements is FALSE? The compound formed?

Ahas formula XY

Bis likely to be ionic

Ccontains X²⁺ ions

Dcontains Y^- ions

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Question 22

jamb 1991

A sample of a gas exerts a pressure of 8.2 atm when confined in a 2.93 dm³ container at 20°C. The number of moles of gas in the sample is?

(R = 0.082 litre atm / deg mole)

A1.00

B2.00

C3.00

D4.00

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Question 23

jamb 1991

A given quantity of a gas occupies a volume of 228 cm³ at a pressure of 750mm Hg. What will be its volume at atmospheric pressure?

A220 cm³

B225 cm³

C230 cm³

D235 cm³

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Question 24

jamb 1991

Calculate the volume of carbon (IV)oxide measured at s.t.p, produced when 1 kg of potassium hydrogen trioxocarbonate (IV) is totally decomposed by heat?

(G.M.V. at s.t.p 22.4 dm³, K = 39, O = 16, C = 12, H = 1)

A28 dm³

B56 dm³

C112 dm³

D196 dm³

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Question 25

jamb 1991

30cm\(^3\) of oxygen at 10 atmospheres pressure is placed in a 20 cm\(^3\) container. Calculate the new pressure if temperature is kept constant?

A6.7 atm

B15.0 atm

C60.0 atm

D66. 0 atm

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Question 26

jamb 1991

In two separate experiments, 0.36g and 0.71g of chlorine combined with a metal X to give Y and Z respectively. An analysis showed that Y and Z contain 0.20g and 0.40g of X respectively. The data above represents the law of ?

Amultiple proportion

Bconservation of mass

Cconstant composition

Dreciprocal proportion

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Question 27

jamb 1991

An iron ore is known to contain 70.0% Fe₂O₃. The obtain from 80kg of the ore is?

(Fe = 56, O = 16)

A35.0 kg

B39.2 kg

C70.0 kg

D78.4 kg

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Question 28

jamb 1991

Which of the following are mixtures?
i, Petroleum
ii, Rubber latex
iii. Vulcanizer's solution
iv, Carbon (II)sulphide

Ai, ii and iii

Bi, ii and iv

Ci and ii only

Di and iv

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Question 29

jamb 1991

Which of the following can be obtained by fractional distillation?

ANitrogen from liquid air

BSodium chloride from sea water

CIodine from a solution of Iondine in carbon tetrachloride

DSulphur from a solution of sulphur incarbon disulphide

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