Year : 
1980
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

1 - 10 of 47 Questions

# Question Ans
1.

In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture?

A. Fractional distillation

B. crystallization

C. Filtration followed by evaporation

D. Evaporation followed by sublimation

E. Filtration followed by sublimation

D

2.

The alloy duralumin is used for the building of aeroplanes because it?

A. asborbs heat readily from sure thereby preventing the inside of the plane from getting cold at high attitudes

B. reflects sunlight readily, thereby keeping the inside of the plane cool

C. is extremely durable and possesses reflective ability

D. is easily the lightest building material

E. possesses both strenght and lightness

E

3.

A solution X on mixing with AgNO3 solution, gives a white precipitate solution in NH3. A Solution Y, when added to X, also gives a white precipiate which is soluble on boiling. Solution Y contains?

A. Ag+ion

B. Pb2+ion

C. Pb4+ion

D. Zn2+ion

E. Al3+ion

B

4.

10cm3 of CO is mixed and sparked with 100cm3 of air containing 21% O2. If all the volumes measured at S.T.P. the volume of resulting gases would be?

A. 90cm3

B. 100cm3

C. 105cm3

D. 110cm3

E. 115cm3

Detailed Solution

2CO(g) + O2(g) ---> 2CO\(_2\)(g)
2vol 1vol 2vol
Volume in cm\(^3\) Before sparking: 10 // 21
Volume in cm\(^3\) On sparking 10 // 5 // 10
Volume in cm\(^3\) After sparking: 0// 16 // 10
Total volume of resulting gas = Volume of [excess oxygen + CO\(_2\) produced + unreactive components]
= 16 + 10 + 79 → 105cm\(^3\)
5.

A sample of an oxide of mercury weighed 1.00g. When this was heated, oxygen was given off, and 1.00g of mercury metal only was left. What is the formula of the oxide?

A. Hg2O

B. HgO2

C. HgO2

D. HgO

E. None of the above

Detailed Solution

Various oxides of mercury: Mercury(I) oxide (mercurous oxide), Hg\(_2\)O. Mercury(II) oxide (mercuric oxide), HgO.
No specific oxide of mercury is refered in the question.
6.

On heating, under suitable conditions, 1 litres of monoatomic gas,X, combines with 11/2 litres of an oxide, What is the formula of the oxide.

A. XO3

B. X2O3

C. X3O2

D. XO2

E. None of the above

B

7.

If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litre of water,and resulting solution mixed thoroughly, the resulting sulpuric acid concentration will be?

A. 2.2 M

B. 1.1 M

C. O.22 M

D. 11 M

E. 0.20 M

C

8.

Which of the following reactions is correct as as written?

A. FeCl2 + 3NH4OH → Fe(OH)3 + 3NH4Cl

B. Pb2O3 + 4HCl → PbCl2 + 2H2O

C. PbNO3 + H2S → PbS + 2HNO3

D. NaOH + H2SO4 → NaHSO4 +H2O

E. 2NH4NO3 → N2 + 2H2O

D

9.

Under high pressure, real gases do not obey gas laws because their molecules?

A. have become more energetic

B. have become less energetic

C. have become smaller in size

D. decompose into atoms

E. start repelling each other

Detailed Solution

Van der Waals noticed the behavior of real gases at low temperature and high pressure possesses weak but short range forces.
10.

How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves in 500cm3 of 6M HCl?


(Mg=24, H=1, Cl=35.5)

A. 1.2 g

B. 0.7 g

C. 0.5 g

D. 0.3 g

E. 0.12 g

Detailed Solution

Mg + 2HCl → MgCl2 + H2
6 molar contains 6 Χ 36.5 gms 1000 cc

Solution i.e 6 Χ 36.5/2gms in 500 cc
= 3 Χ 36.5
24 gms of mg will react with 2 Χ 36.5 HCl to liberate 2 gm of hydrogen
∴ 6 gms will liberate 6 Χ 2/24 Χ 1 = 0.5 gm of H2
1.

In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture?

A. Fractional distillation

B. crystallization

C. Filtration followed by evaporation

D. Evaporation followed by sublimation

E. Filtration followed by sublimation

D

2.

The alloy duralumin is used for the building of aeroplanes because it?

A. asborbs heat readily from sure thereby preventing the inside of the plane from getting cold at high attitudes

B. reflects sunlight readily, thereby keeping the inside of the plane cool

C. is extremely durable and possesses reflective ability

D. is easily the lightest building material

E. possesses both strenght and lightness

E

3.

A solution X on mixing with AgNO3 solution, gives a white precipitate solution in NH3. A Solution Y, when added to X, also gives a white precipiate which is soluble on boiling. Solution Y contains?

A. Ag+ion

B. Pb2+ion

C. Pb4+ion

D. Zn2+ion

E. Al3+ion

B

4.

10cm3 of CO is mixed and sparked with 100cm3 of air containing 21% O2. If all the volumes measured at S.T.P. the volume of resulting gases would be?

A. 90cm3

B. 100cm3

C. 105cm3

D. 110cm3

E. 115cm3

Detailed Solution

2CO(g) + O2(g) ---> 2CO\(_2\)(g)
2vol 1vol 2vol
Volume in cm\(^3\) Before sparking: 10 // 21
Volume in cm\(^3\) On sparking 10 // 5 // 10
Volume in cm\(^3\) After sparking: 0// 16 // 10
Total volume of resulting gas = Volume of [excess oxygen + CO\(_2\) produced + unreactive components]
= 16 + 10 + 79 → 105cm\(^3\)
5.

A sample of an oxide of mercury weighed 1.00g. When this was heated, oxygen was given off, and 1.00g of mercury metal only was left. What is the formula of the oxide?

A. Hg2O

B. HgO2

C. HgO2

D. HgO

E. None of the above

Detailed Solution

Various oxides of mercury: Mercury(I) oxide (mercurous oxide), Hg\(_2\)O. Mercury(II) oxide (mercuric oxide), HgO.
No specific oxide of mercury is refered in the question.
6.

On heating, under suitable conditions, 1 litres of monoatomic gas,X, combines with 11/2 litres of an oxide, What is the formula of the oxide.

A. XO3

B. X2O3

C. X3O2

D. XO2

E. None of the above

B

7.

If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litre of water,and resulting solution mixed thoroughly, the resulting sulpuric acid concentration will be?

A. 2.2 M

B. 1.1 M

C. O.22 M

D. 11 M

E. 0.20 M

C

8.

Which of the following reactions is correct as as written?

A. FeCl2 + 3NH4OH → Fe(OH)3 + 3NH4Cl

B. Pb2O3 + 4HCl → PbCl2 + 2H2O

C. PbNO3 + H2S → PbS + 2HNO3

D. NaOH + H2SO4 → NaHSO4 +H2O

E. 2NH4NO3 → N2 + 2H2O

D

9.

Under high pressure, real gases do not obey gas laws because their molecules?

A. have become more energetic

B. have become less energetic

C. have become smaller in size

D. decompose into atoms

E. start repelling each other

Detailed Solution

Van der Waals noticed the behavior of real gases at low temperature and high pressure possesses weak but short range forces.
10.

How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves in 500cm3 of 6M HCl?


(Mg=24, H=1, Cl=35.5)

A. 1.2 g

B. 0.7 g

C. 0.5 g

D. 0.3 g

E. 0.12 g

Detailed Solution

Mg + 2HCl → MgCl2 + H2
6 molar contains 6 Χ 36.5 gms 1000 cc

Solution i.e 6 Χ 36.5/2gms in 500 cc
= 3 Χ 36.5
24 gms of mg will react with 2 Χ 36.5 HCl to liberate 2 gm of hydrogen
∴ 6 gms will liberate 6 Χ 2/24 Χ 1 = 0.5 gm of H2