Question

Magnesium and nitrogen react in a combination reaction to produce magnesium nitride: 3 Mg + N2→ Mg3N2 In a particular experiment, a 5.65-g sample of N2 reacts completely. The mass of Mg consumed is ________ g.

Answer 1

Answer: The mass of magnesium consumed will be 14.731 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 nitrogen gas = 5.65 g

Molar mass of nitrogen gas = 28 g/mol

Putting values in above equation, we get:

$\text{Moles of }N_2=\frac{5.65g}{28g/mol}=0.202mol$

For the given chemical equation:

$3Mg+N_2\rightarrow Mg_3N_2$

By Stoichiometry of the reaction:

1 mole of nitrogen gas reacts with 3 moles of magnesium.

So, 0.202 moles of nitrogen gas will react with = $\frac{3}{1}\times 0.202=0.606mol$ of magnesium.

Now, calculating the mass of magnesium by using equation 1, we get:

Moles of magnesium = 0.606 moles

Molar mass of magnesium = 24.31 g/mol

Putting values in equation 1, we get:

$0.606mol=\frac{\text{Mass of magneisum}}{24.31g/mol}\\\\\text{Mass of magnesium}=14.731g$

Hence, the mass of magnesium consumed will be 14.731 g.