What is the mass of 0.443 mol of hydrazine, N2H4? Use N = 14.007 and H = 1.008 g/mol.

1. Build the molar mass first: nitrogen contributes 2 x 14.007 = 28.014 g/mol. 2. Hydrogen contributes 4 x 1.008 = 4.032 g/mol, so the molar mass is 32.05 g/mol. 3. Mass equals moles times molar mass: 0.443 mol x 32.05 g/mol = 14.2 g. 4. The value 12.4 g uses only the nitrogen part of the molar mass, dropping the four hydrogen atoms. 5. The value 0.0138 g divides the moles by the molar mass instead of multiplying. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.1 Formula Mass and the Mole Concept_