# Water consists of hydrogen and oxygen, and the approximate ratio, by mass, of hydrogen to oxygen is ...

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?

## Answer/Solution

112

### Steps/Work

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 C.

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 C.