Consider the following statements: I. At the same temperature, the mass of vapour above water in two closed vessels is proportional to the free space above the liquid (ideal behaviour assumed). II. Th

Question

Consider the following statements:

I. At the same temperature, the mass of vapour above water in two closed vessels is proportional to the free space above the liquid (ideal behaviour assumed).

II. The vapour pressure of water depends on the volume of free space above the liquid.

III. In a mixture of gases at the same temperature and volume, the partial pressure of a gas is proportional to its number of moles.

IV. If the temperature of a closed container is doubled, the number of molecules in it doubles.

Which statements are correct?

TestHub · Accepted Answer

I The vapour pressure is the same in both vessels at one temperature, so mass = $P V M$ / $RT$ is proportional to $V$ : true.

II Vapour pressure depends only on the liquid and the temperature, not on free volume: false.

III p = $n RT$ / $V$ , so p is proportional to $n$ : true.

IV The container is closed, so the number of molecules does not change: false.

Correct: I and III only. Answer: ( $C$ ).

Chemistry - Ideal Gas Question with Solution | TestHub

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