Question

calculate the percentage by mass, of carbon in albuterol, c₁₃h₂₁no₃. given carbon is 12.0 g/mol, hydrogen is 1.0 g/mol, nitrogen is 14.0 g/mol, and oxygen is 16 g/mol.
a 65.3%
b 34.2%
c 0.34
d 50.2%
e none of the above

Explanation:

Step1: Calculate molar mass of albuterol

$M = 13\times12.0+21\times1.0 + 14.0+3\times16$
$M=156 + 21+14 + 48$
$M = 239\ g/mol$

Step2: Calculate mass of carbon in albuterol

Mass of carbon $=13\times12.0 = 156\ g/mol$

Step3: Calculate mass - percentage of carbon

Mass - percentage of carbon $=\frac{156}{239}\times100\%$
$=\frac{15600}{239}\% \approx 65.3\%$

Answer:

A. 65.3%