Year : 
1999
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

1 - 10 of 49 Questions

# Question Ans
1.

200cm3 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]

A. 2.78g

B. 5.56g

C. 8.34g

D. 11.12g

Detailed Solution

The balanced equation of the reaction is:
Pb(NO3)2(aq) + 2HCl(aq) ---> PbCl2(s) + 2HNO3(aq)
From the balanced equation,
1 mole of Pb(NO3)2 gave 1 mole of PbCl2
using, molar concentration = no of moles/volume in dm3
therefore, no of moles = molar concentration x volume in dm3
where, molar concentration of Pb(NO3)2 = 0.1M
volume of Pb(NO3)2 in dm3 = 0.2 dm3
therefore, no of moles of Pb(N
2.

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]

A. 11.00

B. 22.00

C. 33.00

D. 44.00

Detailed Solution

56.00cm3 of a gas at S.T.P weighed 0.11g
Molar volume of the gas = 22.4dm3 = 22400cm3
molar mass = (22400 x 0.11)/56
molar mass = 2464/56 = 44
Vapour density = Molar mass/2 = 44/2 = 22
3.

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

A. Propane

B. Oxygen

C. Methane

D. Ammonia

C
4.

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?

A. 91K

B. 182K

C. 273K

D. 819K

Detailed Solution

From P1/T1 = P2/T2 = 9/273 = 3/T2
T2 x 9 = 273 x 3
T2 = (273 x 3)/9
T2 = 91K
5.

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

A. Helium

B. Magnesium

C. Copper pyrites

D. Glass

B
6.

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]

A. 0.3g

B. 1.5g

C. 2.4g

D. 3.0g

Detailed Solution

Molar conc. =no.of moles／Vol in dm3
Vol=250cm3= 0.25dm3
Molar conc=0.5M
No of moles=molar conc *Vol in dm3
=0.5*0.25
=0.125mole of HCl
2moles of HCl → １Mole of Mg
0.125 mole →(0.125*1)/2
=0.0625mole of Mg
Reacting mass=no of moles* molar mass
Mg=24
Mass=0.0625*24
=1.5g
7.

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

A. MCl

B. MCl2

C. MCl3

D. M2Cl6

Detailed Solution

Percentage by mass of M = 20.22%
Percentage by mass of Cl = ?
100 - 20.22 = 79.78%
Mass given ration of M
M = 20.22/27 = 0.75
Chlorine = 79.78/35.5 = 2.24
Divide by the smallest
M = 0.75/0.75 = 1
Cl = 2.24/0.75 = 3
∴ The formula = MCl3
8.

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

A. Ice at -10°C

B. Ice at 0°C

C. Water at 100°C

D. Steam at 100°C

Detailed Solution

The gaseous state of matter has the most disorderly arrangement of particles. Hence, steam (water in gaseous form) is the most disorderly arrangement on the list.
9.

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

A. electron affinity

B. ionization energy

C. activation evergy

D. electronegativity

B
10.

Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains

A. water vapour

B. oxygen

C. carbon (IV) oxide

D. rare gases

D
1.

200cm3 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]

A. 2.78g

B. 5.56g

C. 8.34g

D. 11.12g

Detailed Solution

The balanced equation of the reaction is:
Pb(NO3)2(aq) + 2HCl(aq) ---> PbCl2(s) + 2HNO3(aq)
From the balanced equation,
1 mole of Pb(NO3)2 gave 1 mole of PbCl2
using, molar concentration = no of moles/volume in dm3
therefore, no of moles = molar concentration x volume in dm3
where, molar concentration of Pb(NO3)2 = 0.1M
volume of Pb(NO3)2 in dm3 = 0.2 dm3
therefore, no of moles of Pb(N
2.

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]

A. 11.00

B. 22.00

C. 33.00

D. 44.00

Detailed Solution

56.00cm3 of a gas at S.T.P weighed 0.11g
Molar volume of the gas = 22.4dm3 = 22400cm3
molar mass = (22400 x 0.11)/56
molar mass = 2464/56 = 44
Vapour density = Molar mass/2 = 44/2 = 22
3.

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

A. Propane

B. Oxygen

C. Methane

D. Ammonia

C
4.

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?

A. 91K

B. 182K

C. 273K

D. 819K

Detailed Solution

From P1/T1 = P2/T2 = 9/273 = 3/T2
T2 x 9 = 273 x 3
T2 = (273 x 3)/9
T2 = 91K
5.

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

A. Helium

B. Magnesium

C. Copper pyrites

D. Glass

B
6.

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]

A. 0.3g

B. 1.5g

C. 2.4g

D. 3.0g

Detailed Solution

Molar conc. =no.of moles／Vol in dm3
Vol=250cm3= 0.25dm3
Molar conc=0.5M
No of moles=molar conc *Vol in dm3
=0.5*0.25
=0.125mole of HCl
2moles of HCl → １Mole of Mg
0.125 mole →(0.125*1)/2
=0.0625mole of Mg
Reacting mass=no of moles* molar mass
Mg=24
Mass=0.0625*24
=1.5g
7.

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

A. MCl

B. MCl2

C. MCl3

D. M2Cl6

Detailed Solution

Percentage by mass of M = 20.22%
Percentage by mass of Cl = ?
100 - 20.22 = 79.78%
Mass given ration of M
M = 20.22/27 = 0.75
Chlorine = 79.78/35.5 = 2.24
Divide by the smallest
M = 0.75/0.75 = 1
Cl = 2.24/0.75 = 3
∴ The formula = MCl3
8.

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

A. Ice at -10°C

B. Ice at 0°C

C. Water at 100°C

D. Steam at 100°C

Detailed Solution

The gaseous state of matter has the most disorderly arrangement of particles. Hence, steam (water in gaseous form) is the most disorderly arrangement on the list.
9.

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

A. electron affinity

B. ionization energy

C. activation evergy

D. electronegativity

B
10.

Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains

A. water vapour

B. oxygen

C. carbon (IV) oxide

D. rare gases

D