Question

Combustion analysis of an unknown compound provides the following data: 73.5 grams C, 4.20 grams H, and 72.3 grams Cl. What is the percent composition of each element in this compound?

Answer 1

C- 49%
H- 2.8%
Cl- 48.2%

Answer 2

Answer: Cl = 49.0%, H = 2.8% and Cl = 48.2%

Explanation: Masses of C, H and Cl elements are given and the question asks to calculate the percent composition of each element in the compound.

The formula used for percent composition that is mass percentage is:

mass percent of an element = $(\frac{element mass}{compound mass})*100$

Given:

mass of C = 73.5 grams

mass of H = 4.20 grams

mass of Cl = 72.3 grams

Mass of compound = 73.5 grams + 4.20 grams + 72.3 grams = 150 grams

percent composition of C = $(\frac{73.5}{150})*100$  = 49.0%

percent composition of H = $(\frac{4.20}{150})*100$  = 2.8%

percent composition of Cl = $(\frac{72.3}{150})*100$  = 48.2%

So, the compound has 49.0% C, 2.8% H and 48.2% Cl.