Question

Calculate the mass of chromium produced from 50g of Cr2O3.

Answer 1

Answer: 34 gram of chromium produced from 50g of $Cr_2O_3$

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$    

$\text{Moles of} Cr_2O_3=\frac{50g}{152g/mol}=0.33moles$

The decomposition of $Cr_2O_3$ follows the equation :

$2Cr_2O_3\rightarrow 4Cr+3O_2$  

According to stoichiometry :

2 moles of $Cr_2O_3$ produce = 4 moles of $Cr$

Thus 0.33 moles of $Cr_2O_3$ will produce=$\frac{4}{2}\times 0.33=0.66moles$  of $Cr$

Mass of $Cr=moles\times {\text {Molar mass}}=0.66moles\times 52g/mol=34g$

Thus 34 gram of chromium produced from 50g of $Cr_2O_3$