help with both i dont understand how to do these

Caffeine (MW 194.2g/mol ) is a stimulant found in coffee, tea, many soft drinks, and chocolate. Elemental analysis of caffeine shows 49.47 mass \% C, 5.19%H,28.86%N, and 16.48%O. What is the molecular formula of caffeine? Enter in the following order: CHNO Write a balanced equation for the important atmospheric reaction depicted below (carbon is black; axygen is red): e.g. 2N2+2O2 goes to 4NO (no spaces between coefficient and compound and the +, spaces between goes to) [1]