# A substance contains 35.0 g nitrogen, 5.05 g hydrogen, and 60.0 g of oxygen. How many grams of hydrogen are there in a 142-g sample of this substance?

Apr 12, 2017

There will be 7.17 g of hydrogen in the 142-g sample.

#### Explanation:

We need to dtermine what is known as the "percent composition by mass" for this compound. Then, the portion of a larger sample can be found.

The total mass of the three elements is 100.05 g, which means that the percentages are virtually the same as the given masses:

% N = $\frac{35.0}{100.05} \times 100$ = 34.98 %

% H = $\frac{5.05}{100.05} \times 100$ = 5.047 %

% O = $\frac{60.0}{100.05} \times 100$ = 59.97 %

While only the middle value is required, it is worthwhile to find all three in the event that we need the other information in a follow-up problem.

Since 5.047 % of the mass is due to hydrogen, we can now multiply this percentage by any otherr mass:

0.05047 xx 142 = 7.17 g of hydrogen