JAMB Chemistry Past Questions & Answers - Page 99

491.

Which of the following conduct electricity?

A.

sulfur

B.

graphite

C.

diamond

D.

red phosphorus

E.

yellow phosphorus

Correct answer is B

No explanation has been provided for this answer.

492.

When 50cm3 of a saturated solution of sugar (molar mass 342.0g) at 40oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40oC is

A.

10.0 moles dm-3

B.

7.0 moles dm-3

C.

3.5 moles dm-3

D.

2.0 moles dm-3

Correct answer is D

No explanation has been provided for this answer.

493.

Which of the following groups of physical properties increases from left to right of the periodic table?

i. Ionization energy ii. Atomic radius iii. Electronegativity iv. Electron affinity

A.

i and ii

B.

i, ii and iii

C.

iii and iv

D.

i, iii and iv

Correct answer is D

Atomic radius is the distance from the atom's nucleus to the outer edge of the electron cloud. In general, atomic radius decreases across a period and increases down a group. 

494.

An element with atomic number twelve is likely to be

A.

electrovalent with a velocity of 1

B.

electrovalent with a valency of 2

C.

covalent with a valency of 2

D.

covalent with valency of 4

Correct answer is B

No explanation has been provided for this answer.

495.

The relationship between the velocity (U) of gas molecules and their relative molecular mass (M) is shown by the equation

A.

U = (kM)\(\frac{1}{2}\)

B.

U = (kM)2

C.

U = \(\sqrt{\frac{k}{m}}\)

D.

U = \(\frac{k}{m}\)

Correct answer is C

The relationship between (U) of a gas molecule and the relative molecular mass is \(\bar{U}\) = (\(\frac{k}{m}\))\(^{\frac{1}{2}}\)

or \(\bar{U}\) = \(\sqrt{\frac{k}{m}}\)