a) 0.5 mole of N2 gas :
Mass of one mole of N2 gas = 28 g. (∵ Molecular wt. of N2 = 28)
Mass of 0.5 mole of N2 gas = 28 × 0.5 = 14 g
b) 0.5 mole of N atoms :
Mass of one mole of N atoms = 14 g (∵ Atomic wt. of N = 14)
Mass of 0.5 mole of N atoms = 14 × 0.5 = 7 g
c) 3.011 × 1023 number of N atoms :
Mass of 6.022 × 1023 number of N atoms = 14 g
Mass of 3.011 x 1023 number of N atoms = \(\frac{3.011\,\times\,10^{23}}{6.022\,\times\,10^{23}}\,\times\,14\) = 7 g.
d) 6.022 × 1023 number of N2 molecules :
Mass of 6.022 × 1023 number of N2 molecules = 28 g