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 135 grams of water?	Select.
A) 16
B) 72
C) 112
D) 120
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   135*8/9= 
<gadget id="calculator">  135*8/9</gadget>
<output>120</output>
120 grams of oxygen in 135 grams of water.   Answer: 120.
<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 135 grams of water?