the vapour density of a gas may be defined as
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Correct Answer: Option B
Explanation:
The correct answer is B: the mass of a unit volume of the gas compared to an equal volume of hydrogen.
Vapour density is defined as the ratio of the mass of a certain volume of gas to the mass of an equal volume of hydrogen gas, measured under the same conditions of temperature and pressure.
Since hydrogen has a relative molecular mass of 2 (Hâ‚‚), vapour density is effectively half the molar mass of the gas.
Mathematically:
\[
\text{Vapour density} = \frac{\text{Mass of the gas}}{\text{Mass of an equal volume of hydrogen}} = \frac{Molar\ mass\ of\ the\ gas}{2}
\]
So, option B is the correct definition of vapour density.
The correct answer is B: the mass of a unit volume of the gas compared to an equal volume of hydrogen.
Vapour density is defined as the ratio of the mass of a certain volume of gas to the mass of an equal volume of hydrogen gas, measured under the same conditions of temperature and pressure.
Since hydrogen has a relative molecular mass of 2 (Hâ‚‚), vapour density is effectively half the molar mass of the gas.
Mathematically:
\[
\text{Vapour density} = \frac{\text{Mass of the gas}}{\text{Mass of an equal volume of hydrogen}} = \frac{Molar\ mass\ of\ the\ gas}{2}
\]
So, option B is the correct definition of vapour density.