Question

Air bags in cars operate according to the reaction below. How many grams of nitrogen gas are produced during the decomposition of 3.25 g Na3N?

Answer 1

Answer : The mass of nitrogen gas produced during the decomposition of $Na_3N$ are, 0.546 grams.

Solution : Given,

Mass of $Na_3N$ = 3.25 g

Molar mass of $Na_3N$ = 83 g/mole

Molar mass of $N_2$ = 28 g/mole

First we have to calculate the moles of $Na_3N$.

$\text{ Moles of }Na_3N=\frac{\text{ Mass of }Na_3N}{\text{ Molar mass of }Na_3N}=\frac{3.25g}{83g/mole}=0.039moles$

Now we have to calculate the moles of $MgO$

The balanced chemical reaction will be,

$2Na_3N\rightarrow N_2+6Na$

From the balanced reaction we conclude that

As, 2 mole of $Na_3N$ react to give 1 mole of $N_2$

So, 0.039 moles of $Na_3N$ react to give $\frac{0.039}{2}=0.0195$ moles of $N_2$

Now we have to calculate the mass of $N_2$

$\text{ Mass of }N_2=\text{ Moles of }N_2\times \text{ Molar mass of }N_2$

$\text{ Mass of }N_2=(0.0195moles)\times (28g/mole)=0.546g$

Therefore, the mass of nitrogen gas produced during the decomposition of $Na_3N$ are, 0.546 grams.