And what I do is I convert this guy to fraction and this guy to fraction by dividing each guy by 100. And then I multiply each guy by my 100 grams of compound to find how many grams of each is in my compound. So, 100 grams of my compound multiplied by 0.111 which I got this guy divided by 100 equals eleven point 11 grams of h in my 100 grams of compound. Now, likewise, I multiply 100 grams times 0.8
889. This gives me 88.89 grams of oxygen in my 100 grams of compound. Now I have to convert my grams to moles.