Question

Hydrocortisone valerate is an ingredient in hydrocortisone cream what is the percent by mass of carbon

Answer 1

The chemical formula of hydrocortisone valerate is C26H38O6. First, we determine the molar mass of the substance by adding up all the products of the number of atoms and the molar mass of atoms as shown below.
                        molar mass = 26(12) + 38(1) + 6(16) = 446 g/mol
Since, there are 26 atoms of carbon in each molecule, the mass of carbon in each mole is 
                     mass of carbon = (26)(12) = 312
Obtaining the percent by mass of carbon,
                           % by mass of carbon = (312/446) x 100 % 
                                                                 = 69.955%
Thus, the percent by mass of carbon in hydrocortisone valerate is approximately 69.96%.