Caffeine has been found to contain carbon, hydrogen, oxygen and nitrogen only. The percentage carbon was 49.48%, hydrogen was 5.19% and nitrogen was 28.85%. What is the percentage of oxygen in the compound?
We can start by using the fact that the percentages must add up to 100%.
49.48% + 5.19% + 28.85% + % oxygen = 100%
Simplifying this equation:
% oxygen = 16.48%
Therefore, the percentage of oxygen in caffeine is 16.48%.