Question: how many grams of oxygen are there in 144 grams of water?
Answer: Approximately how many grams of oxygen are there in 144 grams of water? Since the ratio, by mass, of hydrogen to oxygen is 2:16, then oxygen is 16/(2+16)=8/9 of mass of water. Therefore there are 144*8/9=128 grams of oxygen in 144 grams of water.