Question

Powdered zinc metal reacts with sulphur (S8) when heated to produce zinc sulphide.



a. )What mass of product can be produced with 25 g of zinc?

b.) What is the actual yield if the percentage yield was 80%?

Answer 1

22092, Chemistry, Other | Completed

Powdered zinc metal reacts with sulphur (S8) when heated to produce zinc sulphide.

a.) What mass of product can be produced with 25 g of zinc?

b.) What is the actual yield if the percentage yield was 80%?

Solution:

The equation of the reaction is:

$$\mathrm{Zn} + \mathrm{S} = \mathrm{ZnS}$$

Begin by determining the molar mass of each compound involved in the reaction.

Using atomic masses from the periodic table, we will find the following:

$$\begin{array}{l} \mathrm{M}(\mathrm{ZnS}) = 97.43\ \mathrm{g/mol}; \\ \mathrm{Ar}(\mathrm{Zn}) = 65.37\ \mathrm{g/mol}. \end{array}$$

a) The mass of product determine from the equation of the reaction:

$$\begin{array}{l} \mathrm{Zn} + \mathrm{S} = \mathrm{ZnS} \\ \mathrm{m}(\mathrm{ZnS}) = \frac{97.43 \cdot 25}{65.37} = 37.26\ \mathrm{g} \end{array}$$

b) The actual yield of ZnS is:

$$\mathrm{m}(\mathrm{ZnS}) = 37.26 \times 0.8 = 29.81\ \mathrm{g}.$$

Answer:

a) The theoretical mass of ZnS is 37.26 g;

b) The actual yield of ZnS is: 29.81 g.