Question

Calculate how many grams of the product form when 16.7 g of oxygen gas completely reacts with solid chromium. Assume that there is more than enough of the solid chromium.

Answer 1

Answer: The mass of product formed is 79.344 g.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$     .....(1)

Given mass of oxygen = 16.7 g

Molar mass of oxygen = 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of oxygen}=\frac{16.7g}{32g/mol}=0.522mol$

The chemical reaction for the formation of chromium oxide follows the equation:

$4Cr+3O_2\rightarrow 3Cr_2O_3$

By Stoichiometry of the reaction:

3 moles of oxygen produces 3 moles of chromium oxide.

So, 0.522 moles of oxygen will produce = $\frac{3}{3}\times 0.522=0.522mol$ of chromium oxide.

Now, calculating the mass of chromium oxide from equation 1, we get:

Molar mass of chromium oxide = 152 g/mol

Moles of chromium oxide = 0.522 moles

Putting values in equation 1, we get:

$0.522mol=\frac{\text{Mass of chromium oxide}}{152g/mol}\\\\\text{Mass of chromium oxide}=79.344g$

Hence, the mass of chromium oxide produced in the given reaction is 79.344 grams.