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?
(A)16
(B)72
(C)112
(D)128
(E)142
-thanx
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StarDust845
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Some more explanation behind the answer for you ....
Ratio of hydrogen to oxygen is 2:16
So we know for every 2 grams of hydrogen there will be 16 grams of oxygen. In this instance we will have a total of 18 grams.
So in every 18 grams of water, there will be 16 grams of oxygen.
Can be written as a fraction: 16/18 (16 parts of the 18 whole)
So we want to find how many grams of oxygen there are in 144 grams of water.
We are looking for x/144 (x parts of the 144 whole).
So we use 16/18 and x/144 and cross multiply.
16x144 = 18x
2304=18x
So x = 2304/18 = 128
Answer is D.
P.S. Where did you get this question from ?
Thanks
Ratio of hydrogen to oxygen is 2:16
So we know for every 2 grams of hydrogen there will be 16 grams of oxygen. In this instance we will have a total of 18 grams.
So in every 18 grams of water, there will be 16 grams of oxygen.
Can be written as a fraction: 16/18 (16 parts of the 18 whole)
So we want to find how many grams of oxygen there are in 144 grams of water.
We are looking for x/144 (x parts of the 144 whole).
So we use 16/18 and x/144 and cross multiply.
16x144 = 18x
2304=18x
So x = 2304/18 = 128
Answer is D.
P.S. Where did you get this question from ?
Thanks
