Question

does one gram mole of nitrogen gas occupy 22.4 litre at 300k temperature and under 820 mm pressure

Answer 1

A gram-mole is the mass in grams equal to its formula weight, N₂ formula weight = 28 g and molecular mass = 28 = 18, i.e., gram-mole of N₂ is 28 grams.
$$\begin{gathered} Accordingtoidealgasequation \\ pV=nRT \\ p=820mmofHg=\frac{820}{760}atm \\ V=\frac{nRT}{p}=\frac{1\times 0.0821\times 300}{{\displaystyle \frac{820}{760}}}=22.83L \\ Sothevolumeisslightlyhigherthanthemolarvolume22.4L \end{gathered}$$