We know that 1 mole of any substance at NTP contains Avogadro’s number of molecules.

0.35 Mole of nitrogen contains = 0.35× 6.022 × 10 ^{23 }molecules of N_{2 }

_{ }=2.17 × 10 ^{23}_{ }molecules of N_{2 } Hence there are 2.17 × 10 ^{23}molecules of N_{2} are present in 0.35 mol of N_{2} .