Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is 2:16. Approximately how many grams of oxygen are there in 144 grams of water?	Choose the correct choice from the following answers:
A) 16  B) 72  C) 112  D) 128  E) 142
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= 
<gadget id="calculator">  144*8/9</gadget>
<output>128</output>
128 grams of oxygen in 144 grams of water.   Answer: 128.
<result>D</result>
Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is 2:16. Approximately how many grams of oxygen are there in 144 grams of water?