# A 143.1 g sample of a compound contains 53.4 g of carbon, 6.9 g of hydrogen, 43 g of nitrogen, and some amount of oxygen. What is the mass percent of oxygen in the compound?

Aug 24, 2016

27.8% oxygen

#### Explanation:

Let me start by writing a simple equation

$143.1 = 53.4 + 6.9 + 43 + x$

x stands for amount of oxygen in grams

When you solve this equation, $x = 143.1 - \left(53.4 + 6.9 + 43\right)$

$x = 143.1 - 103.3$

$x = 39.8 g$

Now in percent form

Mass percent of oxygen $100 \cdot \frac{39.8}{143.1}$

=27.8%