JAMB Chemistry Past Questions & Answers - Page 104

516.

The radioactive emission with the least ionization power is

A.

\( \alpha - particles \)

B.

X-rays

C.

\( \gamma -rays \)

D.

\( \beta - rays \)

Correct answer is C

No explanation has been provided for this answer.

517.

How many unpaired electron are in the p-orbitals of a fluorine atom?

A.

3

B.

0

C.

1

D.

2

Correct answer is C

No explanation has been provided for this answer.

518.

When steam is passed over red hot carbon the substances produced are

A.

hydrogen and trioxocarbonate (IV) acid

B.

hydrogen, oxygen and carbon (IV) oxide

C.

hydrogen and carbon (ii) oxide

D.

hydrogen and carbon (IV) oxide

Correct answer is C

Hydrogen and carbon (ii) oxide will be formed when red steam is passed ever red-hot carbon. Option A,B,D are not produced through this process

519.

Calculate the relative molecular mass of Limestone CaCO3, (Ca = 40, C =12, O = 16)

A.

56

B.

100

C.

76

D.

90

Correct answer is B

One molecule of CaCO has 1Ca, 1C and 30 atom relative molecular mass of CaCO3
1 × Ar of Ca +1 × Ar of C +3 × Ar of O
(1 × 40 + 1 × 12 + 3 × 1)
40 + 12 + 48
=100

Option A,C and D will not give 100

520.

In the electrolysis of brine the anode is

A.

platinum

B.

copper

C.

zinc

D.

carbon

Correct answer is D

In the industrial of brine carbon is the anode while mercury is the cathode. Options of A, B, C are not used in brine solution because they are alloy of mercury