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 problem the given data are, p=1 atm, V= 4.1L, T= 300K, m= 7.0g and R = 0.0821L atm `K^(-1) mol^(-1)`.
As PV= `(m)/(M)` RT
`M = (mRT)/(PV)= (7.0 xx 0.0821 xx 300)/(1 xx 4.1)`
M= 42 amu
`therefore d= (m)/(V)`
`d= (7.0)/(4.1)= 1.7 g L^(-1)`