Well, what we do is we take our atomic weight of our H, which is 1 gram/mol and divide that by our molecular weight of this guy or the empirical weight of this guy. And what we get is 14 grams/mol. These guys, these units cancel, and we get one over 14, which is 0.7
114. Now, to get the percent, we multiply by 100 and we get 7.14% by mass of H in ch two. So in this context, our H takes up 7.14% by mass. So now, suppose I want to find my empirical formula given percent by mass.