# How many grams of nitrogen are present in 2 moles of HNO_3?

In 2 moles of nitric acid there are 2 moles of hydrogen atoms, 6 moles of oxygen atoms, and 2 moles of nitrogen atoms. Since the molar mass of nitrogen (atomic nitrogen!) is $14.01 \cdot g$, we simply double the number. From where did I get the molar mass?