7.00 g of a gas occupies a volume of 4.1 L at 300 K and 1 atm pressure. What is the molecular mass of the gas?

Explanation

In the present case,
`P= 1 " atm, " V= 4.1 L, T = 300 K, m= 7.0 g, " and " R=0.0821 L " atm " K^(-1) mol^(-1)`
`:. " " PV = m/M RT`
`:. " " M=(mRT)/(PV)= (7.0 xx0.0821 xx 300)/(1 x 4.1)= 42` amu
and `:. " " d = m/V`
`:. " " d=(7.0)/(4.1)=1.7g L^(-1)`
Hence, the molecular mass of the given gas is 42 amu and its density in the given conditions is `1.7 g L^(-1)`.