Answer
There is a total of 63.0 g in 2.25 mole of $N_2$.
Work Step by Step
1. Determine the molar mass of this compound ($N_2$), and setup the conversion factors:
$N: 14.01g * 2= 28.02g $
$ \frac{1 \space mole \space (N_2)}{ 28.02 \space g \space (N_2)}$ and $ \frac{ 28.02 \space g \space (N_2)}{1 \space mole \space (N_2)}$
2. Calculate the mass:
$ 2.25 \space mole \times \frac{ 28.02 \space g}{1 \space mole} = 63.0 \space g$
