Question

A hydrocarbon is a compound that contains mostly carbon and hydrogen. Calculate the percent composition (by mass) of the following hydrocarbon: C5H12. Enter the percentages of carbon and hydrogen numerically to four significant figures, separated by commas. View Available Hint(s)

Answer 1

Answer: The percentages of carbon and hydrogen numerically to four significant figures is $83.33\%$ and $16.67\%$ respectively.

Explanation:

Molar mass of the compound is the mass of 1 mole of compound which is the sum of masses of each element.

Mass of 1 mole of compound= mass of carbon + mass of hydrogen+ = 5(12) + 12(1)= 72 g.

a) Percentage by mass of carbon =$\frac{\text {mass of carbon}}{\text {Total mass}}\times 100\ %$

Percentage by mass of carbon =$\frac{60}{72}\times 100\%=83.33\%$

b) Percentage by mass of hydrogen =$\frac{\text {mass of hydrogen}}{\text {Total mass}}\times 100\ %$

Percentage by mass of hydrogen =$\frac{12}{72}\times 100\%=16.67\%$