# The amine, which has a hydrogen density of 22.5%, contains 53.5% carbon and 15.5% hydrogen.

The amine, which has a hydrogen density of 22.5%, contains 53.5% carbon and 15.5% hydrogen. Having determined the formula, calculate the sum of the atoms in the compound.

Taking into account these conditions of the problem, we give the general formula of the amine: CnH2n + 1NH2 or RNH2.
Let’s calculate the molar mass if the density for hydrogen is known:
M (RNH2) = M (H2) * D (H2) = 2 * 22.5 = 45 g / mol;
Determine the amount of moles of carbon, hydrogen by the formula:
Y (C) = m / M = 53.5 / 12 = 4.42 mol;
Y (H) = 15.5 / 1 = 15.5 mol;
We find the masses of carbon, hydrogen, nitrogen:
m (C) = 45 * 0.515 = 24 g;
m (H) = 45 * 0.155 = 6.97 g;
m (N) = 45 – (24 + 6.97) = 14.03 g;
Thus, the number of mol of nitrogen can be determined by the formula: Y (N) = m / M = 14.03 / 14 = 1 mol.
Let’s make calculations using the general formula:
CnH2n + 1NH2 = 45;
12n + 2 + 1 + 14 + 2 = 45;
12n = 45-19;
12n = 26;
n = 2;
Molecular formula C2H5NH2 is ethylamine. M (C2H5NH2) = 12 * 2 + 1 * 7 + 14 = 45 g / mol.