Determine the molecular formula of a compound with an empirical formula of NH2 and a formula mass of 32.06 g/mol.

NH

NH2

N2H4

N3H6

The molecular formula is N2H4 (option 3 is correct)

Explanation:

Step 1: Data given

Empirical formula = NH2

Molar mass of the compound = 32.06 g/mol

Atomic mass of N = 14.0 g/mol

Atomic mass of H = 1.01 g/mol

Step 2: Calculate the molar mass of this empirical formula

The empirical formula says for every N atom we have 2H atoms

The molar mass of this empirical formula is:

14.01 + 2*1.01 = 16.03 g/mol

Step 3: Calculate the molecular formula

We have to multiply the empirical formula by n

n = (molar mass of molecular formula / molar mass of empirical formula)

n = 32.06 / 16.03 = 2

Molecular formula = 2*(NH2)

Molecular formula = N2H4

The molecular formula is N2H4 (option 3 is correct)