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JAMB Chemistry Past Questions & Answers - Page 141

701.

The cracking process is very important in the petroleum industry because it.

A.

gives purer products

B.

yields more lubricants

C.

yields more engine fuels

D.

yields more asphalt

E.

yields more candle wax

Correct answer is C

No explanation has been provided for this answer.

702.

3. 06 g of a sample of potassium trioxochlorate (V) (KCIO3) was required to make a saturated solution with 10cm3 of water at 25°C. The solubility of the salt at 25°C is [K =39, Cl = 35.5, O = 16]

A.

5.0 moles dm3

B.

3.0 moles dm3

C.

2.5 moles dm3

D.

1.0 molesv

E.

0.5 moles dm3

Correct answer is C

Molar mass of KCIO3 = 122.5 g/mol

3.06g = 10
xg = 1000

frac3.06100010

= 306g
Molar conc = fracMassconcMolarmass
Molar conc = frac306122.5

= 2.497mol/dm3

704.

Increasing the pressure of a gas

A.

lowers the average kinetic energy of the molecules

B.

decreases the density of the gas

C.

decreases the temperature of the gas

D.

increases the density of the gas

E.

increases the volume of the gas

Correct answer is D

No explanation has been provided for this answer.

705.

Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?

A.

Fractional distillation without a dehydrant

B.

simple distillation with a dehydrant

C.

fractional distillation with a dehydrant

D.

column chromatography

E.

evaporation

Correct answer is C

Fractional distillation with a dehydrant is the most likely separation process to yield high-quality ethanol from palm wine. Adding a dehydrant helps to remove water from the ethanol more effectively during the distillation process, resulting in a higher purity of ethanol. This is important for producing high-quality ethanol suitable for various applications, including consumption or industrial use.