JAMB Chemistry Past Questions & Answers - Page 118

586.

Detergents are better than soaps for laundry because

A.

detergents are synthetic while soaps are not

B.

detergents are more soluble in water than soaps

C.

scum is precipitated when soaps are used with hard water but not with stergents

D.

soaps from soluble saits with ions causing hardness of water while detergents do not

E.

soaps are in bars while detergents are in powder form

Correct answer is C

No explanation has been provided for this answer.

587.

A salt which loses mass when exposed to air is

A.

hygroscopic

B.

deliquescent

C.

efflorescent

D.

fluorescent

E.

effervescent

Correct answer is C

No explanation has been provided for this answer.

588.

The empirical formula of hydrocarbon containing 0. 12 mole of carbon and 0.36 mole of hydrogen is

A.

CH2

B.

CH3

C.

C2H2

D.

C2H4

E.

C2H6

Correct answer is B

No explanation has been provided for this answer.

589.

Given that 32.0g sulphur contains 6.02 x 10 23 sulphur atoms how many atoms are there in 2.70g of aluminium? {Al = 27, S =32}

A.

6.02 x 10 23

B.

3.01 x 1022

C.

6.02 x 1022

D.

5. 08 x 1022

E.

3.01 x 1022

Correct answer is C

27g Aluminium = \(6.02 \times 10^{23}\)

1g Al = \(\frac{6.02 \times 10^{23}}{27}\)

2.7g Al = \(\frac{6.02 \times 10^{23}}{27} \times 2.7\)

= \(6.02 \times 10^{22} Al \) atoms

590.

Which of the following does not affect the rate of a chemical reaction?

A.

Addition or presence of a catalyst

B.

Size of the reacting particles

C.

The enthalpy change for the reaction

D.

Concentration of the reactants

E.

Temperatureat which the reaction is carried out

Correct answer is C

No explanation has been provided for this answer.