JAMB Chemistry Past Questions & Answers - Page 298

1,486.

How many structural isomers can be written for the alkyl bromide, C4H9Br?

A.

3

B.

4

C.

6

D.

8

Correct answer is B

No explanation has been provided for this answer.

1,487.

50 cm3 of sulphur (IV) oxide, 800 cm3 of ammonia, 450 cm3 of hydrogen chloride, 1.0 cm3 of at 15°C. Which of the following is suitable for demonstrating the fountain experiment?

A.

Sulphur (IV) oxide hydrogen chloride

B.

Carbon (IV) oxide and amonia

C.

Amonia and hydrogen chloride

D.

Carbon (IV) oxide and surphur (IV) oxide

Correct answer is C

No explanation has been provided for this answer.

1,488.

A property of a colloidal dispersion which a solution does not have is?

A.

the Tyndall effect

B.

homogeneity

C.

osmotic pressure

D.

surface polarity

Correct answer is A

No explanation has been provided for this answer.

1,489.

A sample of temporary hard water can be prepared in the laboratory by?

A.

disolving calcium chloride in distilled water

B.

saturating lime water with carbon (IV) oxide

C.

saturating distilled water with calcium hydroxide

D.

dissolving sodium hydrogen trioxocarbonate (IV) in some distilled water

Correct answer is B

No explanation has been provided for this answer.

1,490.

The solubility of copper (II) tetraoxosulphate (Iv) is 75g in 100g of water at 100°C and 25g in 100g of water at 30°C. What mass of the salt would crystallize, if 50g of copper (II) tetraoxosulphate (VI) solution saturated at 100°C were cooled to 30°C ?

A.

57.5

B.

42.2

C.

28.6

D.

14.3

Correct answer is D

solute + solvent = solution

at 100oC; 75g + 100g = 175g

at30oC; \(\frac{25g}{50g}\) + 100g = 125g

From 100oC - 30oC; 175g CuSO4 ppt 50g

From 100oC - 30oC; 50g CuSO4 ppt \(\frac{50 \times 50}{175}\) = 14.3