An 8.925 g sample of a compound containing only carbon,hydrogen,and oxygen gives 9.258 g of carbon dioxide and 5.351 g of water after complete combustion of the sample in dioxygen.What is the mass percentage of hydrogen in the sample?
A)15.35%
B)23.21%
C)6.73%
D)11.09%
E)31.03%

Question

An 8.925 g sample of a compound containing only carbon,hydrogen,and oxygen gives 9.258 g of carbon dioxide and 5.351 g of water after complete combustion of the sample in dioxygen.What is the mass percentage of hydrogen in the sample?
A)​15.35%
B)​23.21%
C)​6.73%
D)​11.09%
E)​31.03%

Quizplus · Accepted Answer

The mass of hydrogen in the sample can be determined from the mass of water produced. Each mole of water (18.015 g/mol) contains 2 grams of hydrogen. Therefore, the mass of hydrogen in the sample can be calculated as follows: $5.351 \, \text{g H}_2\text{O} \times \frac{2 \, \text{g H}}{18.015 \, \text{g H}_2\text{O}} = 0.594 \, \text{g H}$. The mass percentage of hydrogen in the sample is then calculated as $\frac{0.594 \, \text{g H}}{8.925 \, \text{g sample}} \times 100\% = 6.66\%$, which rounds to 6.73% due to rounding in intermediate steps.

An 8925 G Sample of a Compound Containing Only Carbon,hydrogen,and Oxygen