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 180 grams of water?	Choices: A) 160 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 180   18x = 180   x = 10   Since x is 10, we know that there are 16 x 10 = 160 grams of oxygen in 180 grams of water.   160nswer 160.
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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 180 grams of water?