Question

Calculate the mass of arsenic trihydride produced from 117.4 g of hydrogen gas with excess arsenic trioxide:

Answer 1

Answer: The mass of $AsH_3$ produced is, 1528.8 grams.

Explanation : Given,

Mass of $H_2$ = 117.4 g

Molar mass of $H_2$ = 2 g/mol

First we have to calculate the moles of $H_2$.

$\text{Moles of }H_2=\frac{\text{Given mass }H_2}{\text{Molar mass }H_2}$

$\text{Moles of }H_2=\frac{117.4g}{2g/mol}=58.7mol$

Now we have to calculate the moles of $AsH_3$

The balanced chemical equation is:

$6H_2+As_2O_3\rightarrow 2AsH_3+3H_2O$

From the reaction, we conclude that

As, 6 moles of $H_2$ react to give 2 moles of $AsH_3$

So, 58.7 moles of $H_2$ react to give $\frac{2}{6}\times 58.7=19.6$ mole of $AsH_3$

Now we have to calculate the mass of $AsH_3$

$\text{ Mass of }AsH_3=\text{ Moles of }AsH_3\times \text{ Molar mass of }AsH_3$

Molar mass of $AsH_3$ = 78 g/mole

$\text{ Mass of }AsH_3=(19.6moles)\times (78g/mole)=1528.8g$

Therefore, the mass of $AsH_3$ produced is, 1528.8 grams.