Problem 120P

Caffeine, a stimulant found in coffee and soda, has the mass percent composition: C, 49.48%; H, 5.19%; N, 28.85%; O, 16.48%. The molar mass of caffeine is 194.19 g/mol. Find the molecular formula of caffeine.

Solution 120P

Step 1:

Given :

Mass percent composition of C = 49.48%

Mass percent composition of H = 5.19%

Mass percent composition of N = 28.85%

Mass percent composition of O = 16.48%

Molar mass of caffeine = 194.19 g/mol

Molecular formula of caffeine = ?

To find the molecular formula, we need to find the number of atoms.

number of moles (n) =

To find the mass of element here, we multiply the mass percent composition with the molar mass of caffeine.

Mass of carbon (C) =194.19 = 96.0852 g

Mass of hydrogen(H) =194.19 = 10.078 g

Mass of nitrogen(N) =194.19 = 56.023 g

Mass of oxygen(O) =194.19 = 32.00 g