Question

If a sample of nitrogen gas (N2) contains 1.2 x 10^24 atoms of nitrogen, then about how many moles of nitrogen gas are in the sample?
5.0
1.0
2.5
3.0

Answer 1

The number of moles of nitrogen gas is  1.0 mole

calculation

N2 is a molecule  therefore;

1  molecule  of N₂  = 2 atoms  of N

          ? molecules= 1.2 x10 ²⁴atoms

by cross  multiplication

=[( 1.2  x 10²⁴ atoms x 1  molecule) / 2 atoms]  = 6 x 10²³  molecules

According to Avogadro's  law  1  mole  =6.02 x 10²³  molecules

                                                                ?  moles= 6.0 x 10²³   molecules

by cross  multiplication

= [(6.0x 10²³  molecules  x 1  mole) / 6.02 x10²³  molecules]  =  1.0  mole