Question

Molecular weight of oxygen is $ 32\, amu $ . At $ STP $ , volume of $ 1\, gm $ of oxygen is $ 700 \,cm^3 $ . What is the value of gas constant $ R $ ?

• A. $ 18.23 \,J \,mol^{-1}\, K^{-1} $
• B. $ 27.73 \,J \,mol^{-1}\, K^{-1} $
• C. $ 37.97 \,J \,mol^{-1}\, K^{-1} $
• D. $ 8.31 \,J \,mol^{-1}\, K^{-1} $

Answer 1

Answer: (D)

$PV=nRT$
At $STP$, $P=10^{5}$,
$T=273$,
$n=\frac{1}{32}$,
$V=700\times10^{-6}m$
$R=\frac{PV}{nT}$
$=\frac{10^{5}\times700\times10^{-6}}{1 32\times273}$
$\simeq 8.31\,J\,mol^{-1}\,K^{-1}$