Question

The mass % of C in methane (CH4) is __________.

Select one:
a. 25.13
b. 133.6
c. 92.26
d. 74.87
e. 7.743

Answer 1

The correct answer is d. 74.87%. Methane, CH4, has one carbon atom and four hydrogen atoms. The molar mass of CH4 is 16.04 g/mol. The mass of carbon in one mole of CH4 is 12.01 g. Therefore, the percent by mass of carbon in CH4 is 12.01/16.04 x 100 = 74.87%.