Answer:
A. to determine the efficiency of the reaction
Explanation:
- Percentage is the ratio of the actual yield to theoretical yield as a percentage. It is calculated by dividing the actual yield by theoretical yield then multiplying by 100%.
- Calculation of percentage yield is important as it helps in the determination of efficiency of a reaction. For example in most industries for the purpose of making the most product with the least waste.
- Additionally, calculating the percentage yield helps in determining other products that may be formed during the reactions.
Proof of the experiment and what happened during the experiment.
Answer: The empirical formula of the metal sulfide is
.
Explanation:
Given: Mass of metal = 20.38 g
Mass of metal sulfide = 31.47 g
Moles is the mass of a substance divided by its molar mass.
So, moles of cobalt (molar mass = 59 g/mol) are as follows.

Moles of bromine (molar mass = 80 g/mol) are as follows.

Now, the ratio of number of moles of cobalt and number of moles of bromine are as follows.
Moles of Co : Moles of Br = 1 : 2
Hence, the empirical formula is
.
Thus, we can conclude that the empirical formula of the metal sulfide is
.