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 126 grams of water?	Choose the correct choice from the following:	A) 16	B) 72	C) 112	D) 128	E) 142
Solution:   We are given that the ratio of hydrogen to oxygen in water, by mass, is 2 : 16. Using our ratio multiplier we can re-write this as 2x : 16x. We can now use these expressions to determine how much oxygen is in 126 grams of water.   2x + 16x = 126   18x = 126   x = 7   Since x is 7, we know that there are 16 x 7 = 112 grams of oxygen in 126 grams of water.   Answer 112.
<result>C</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 126 grams of water?