What is the volume occupied by 1.4 g of N2 at S.T.P?

Get the moles of nitrogen and use the idea of molar volume
Mass of N2 = 1.4 g
Moles of N2 = 1.4g / 28g per mole = 0.05 moles
One mole of N2 at S.T.P has volume = 22.414 dm3
0.05 moles of N2 at S.T.P has volume = 22.414 × 0.05 = 1.12 dm3