Question

An experiment requires that enough CH5N be used to yield 17.8 g of nitrogen.

how much CH5N must be weighted out?

Answer 1

Molar mass of CH5N = atomic mass of carbon + 5 X atomic mass of Hydrogen + atomic mass of Nitrogen

= 12 g/mol+ 5 X 1 g/mol + 14 g/mol = 31 g/mol

Molar mass of N2 = 2 x atomic mass of Nitrogen = 2 x 14 g/mol = 28 g/mol,

Now question can be solved as shown below

Hence, the amount required to be wieghed of CH5N is 39.5 g (if you use more sensitive balance, then 39.42 g).

Thank You