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Chemistry Past Questions

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49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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49 questions

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Question 21

jamb 1999

In order to remove one electron from a 3S orbital of gaseous sodium atom, about 496KJMol^-1 of energy is required. This energy is referred to as

Aelectron affinity

Bionization energy

Cactivation evergy

Delectronegativity

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Question 22

jamb 1999

In which of the following are water molecules in the most disorderly arrangement?

AIce at -10°C

BIce at 0°C

CWater at 100°C

DSteam at 100°C

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Question 23

jamb 1999

A gaseous metallic chloride MClx consists of 20.22% of M by mass. The formula of the chloride is?
[M = 27, Cl = 35.5]

AMCl

BMCl₂

CMCl₃

DM₂Cl₆

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Question 24

jamb 1999

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
From the equation above, the mass of magnesium required to react with 250cm3 of 0.5M HCl is
[Mg = 24]

A0.3g

B1.5g

C2.4g

D3.0g

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Question 25

jamb 1999

Which of the following will have its mass increased when heated in air?

AHelium

BMagnesium

CCopper pyrites

DGlass

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Question 26

jamb 1999

Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume?

A91K

B182K

C273K

D819K

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Question 27

jamb 1999

Which of the following gases will diffuse fastest when passed through a porous plug?
[H = 1, C = 12, N = 14, O = 16]

APropane

BOxygen

CMethane

DAmmonia

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Question 28

jamb 1999

56.00cm³ of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?
[Molar volume of a gas at S.T.P = 22.4dm³]

A11.00

B22.00

C33.00

D44.00

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Question 29

jamb 1999

200cm\(^3\) each of 0.1M solutions of lead (II) trioxonitrate(V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.
[Pb = 207, Cl= 35.5, N = 14, O = 16]

A2.78g

B5.56g

C8.34g

D11.12g

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