JAMB Chemistry Past Questions & Answers - Page 244

1,216.

Fats and oils are?

A.

addition products of long chain fatty acids and alkali

B.

addition products of long-chain fattyy acids and glycerol

C.

condensation products of long-chain fatty acids and glycerol

D.

condensation products of formaldehyde and glycerol

E.

liquids at 20°C

Correct answer is C

No explanation has been provided for this answer.

1,217.

When air is compressed?

A.

its density decreases

B.

it solidifies

C.

its temperature decreases

D.

its temperature increases

E.

its temperature remains unchanged

Correct answer is D

Compressed air is a gas, or a combination of gases, that has been put under greater pressure than the air in the general environment.

When you pressurize a gas by compressing it into a container, you're putting all those molecules into a smaller volume of space and you're adding potential energy by the compression.

Gay Lussac's Law - states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature. 

1,218.

If an organic compound decolorizes bromine water then the compound is?

A.

saturated

B.

supersaturated

C.

unsaturated

D.

a solid

E.

protonated

Correct answer is C

No explanation has been provided for this answer.

1,219.

When sodium nitrate dissolves in water, ∆H is positive. This means that?

A.

the reaction is catalysed

B.

the reaction is complete

C.

the reaction is exothermic

D.

the reaction is endthermic

E.

sodium nitrate is highly soluble in water

Correct answer is D

No explanation has been provided for this answer.

1,220.

Na2CO3 + 2HCI → 2NaCI + H2O + CO2. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
(1 mole of gas occupies 22.4 dm3 at s.t.p)
(Na = 23, C = 12, O = 16)

A.

44.8 dm3

B.

11.2 dm3

C.

100.1 dm3

D.

3.0 dm3

E.

22.4 dm3

Correct answer is B

Na2CO3 + 2HCI → 2NaCI +H2O + CO2
53 gm Na2CO3 will therefore liberate (22.4)/(106) x (53)/(1) = 11.2 dm3