At fixed temperature and `600 mm` pressure, the density of a gas is `42`. At the same temperature and `700 mm` pressure, what is the density of the gas?

Explanation

According to Boyle's Law,
`P prop (1)/(V)` (at constant temperature)
Density (`D`) `=(Mass (m))/(Volume(V))`
or `D prop (1)/(V)`
`:. P prop D`
or `(P_(1))/(D_(1))=(P_(2))/(D_(2))`
`:. D_(2)=(P_(2)xxD_(1))/(P_(1))`
Given `P_(1)=600`, `D_(1)=42`, `P_(2)=700`
`:. D_(2)=(700xx42)/(600)=49`
Hence, the density of the gas is `49`.