JAMB Chemistry Past Questions & Answers - Page 173

861.

One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound

A.

cystallization

B.

hydrolysis

C.

sublimation

D.

filtration

E.

chromatography

Correct answer is E

No explanation has been provided for this answer.

862.

On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced?

A.

SO2 (g) + FeS (s)

B.

SO3 (g) +FeS(s)

C.

SO2 (g) + SO3(g)

D.

SO2 (g) + H2S (g)

E.

SO3(g) + H2S(g)

Correct answer is C

No explanation has been provided for this answer.

863.

Phosphorus burns in oxygen according to the equation P4 + 502 → P4O10. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres]

A.

5. 20

B.

11. 20

C.

2. 24

D.

20. 20

E.

6. 20

Correct answer is B

P4 + 502 → P4O10

for the complete combustion of 124 grammes of phosphorus we need

5 x 22.4 litres of O2

for 12.4 gms of P4 we need

\(\frac{5 \times 22.4}{124} \times \frac{12.4}{1}\)

\(\frac{22.4}{2}\) = 11.2 litres

864.

Bronze is an alloy of

A.

copper, zinc and nickel

B.

aluminium and copper

C.

copper and zinc

D.

tin and zinc

E.

tin and copper

Correct answer is E

No explanation has been provided for this answer.

865.

Two metallic ions associated with hard water are

A.

copper and zinc

B.

magnesium and silver

C.

calcium and magnesium

D.

potassium and tin

E.

sodium and lead

Correct answer is C

No explanation has been provided for this answer.