Question

The theoretical yield of a reaction is the amount of product obtained if the limiting reactant is completely converted to product. Consider the reaction: H2(g) + C2H4(g) → C2H6(g) If 8.150 g H2 is mixed with 9.330 g C2H4, calculate the theoretical yield (g) of C2H6 produced by the reaction.

Answer 1

Answer: 9.9 grams

Explanation:

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

a) moles of $H_2$

$\text{Number of moles}=\frac{8.150g}{2g/mol}=4.08moles$

b) moles of $C_2H_4$

$\text{Number of moles}=\frac{9.330g}{28g/mol}=0.33moles$

$H_2(g)+C_2H_4(g)\rightarrow C_2H_6(g)$

According to stoichiometry :

1 mole of $C_2H_4$ combine with 1 mole of $H_2$

Thus 0.33 mole of $C_2H_4$ will combine with =$\frac{1}{1}\times 0.33=0.33$ mole of $H_2$

Thus $C_2H_4$ is the limiting reagent as it limits the formation of product.

As 1 mole of $C_2H_4$ give =  1 mole of $C_2H_6$

Thus 0.33 moles of $C_2H_4$ give =$\frac{1}{1}\times 0.33=0.33moles$  of $C_2H_6$

Mass of $C_2H_6=moles\times {\text {Molar mass}}=0.33moles\times 30g/mol=9.9g$

Thus theoretical yield (g) of $C_2H_6$ produced by the reaction is 9.9 grams