Chapter 11.4, Problem 34SSC

Interpretation Introduction

Interpretation:

The theoretical yield of Iron sulfide formed by 83.77g of iron with an excess of sulfur needs to be determined.

Concept introduction − The theoretical yield is what would be obtained if the entire limiting reagent reacted to give the product in question.

Answer to Problem 34SSC

Theoretical yield = 155.9g.

Explanation of Solution

Given: In an experiment, $83.77$ gm of iron is combined with an excess of sulfur and then the mixture is heated to obtain iron (III) sulfide.

$2Fe(s)+3S(s)\to F{e}_2{S}_3(s)$

In order to convert mass of iron to moles, we need to divide mass (83.77g) by molar mass of iron (55.84g). We get 1.5 mole of iron.

Now since 2 moles of Fe produces 1 mole of ${\text{Fe}}_2{\text{S}}_3$ Therefore, 1.5 mole of Fe produces

$1.5\text{ mole Fe}\left(\frac{1{\text{ mole Fe}}_2{\text{S}}_3}{2\text{ mole Fe}}\right)=\text{ 0}{\text{.75 mole Fe}}_2{\text{S}}_3$

In order to convert mole of ${\text{Fe}}_2{\text{S}}_3$ to mass, we need to multiply mole by molar mass of ${\text{Fe}}_2{\text{S}}_3$. We get 155.9g of ${\text{Fe}}_2{\text{S}}_3$.

Conclusion

Thus, theoretical yield = 155.9g.