# Question #1d3d1

##### 1 Answer

Jan 26, 2018

x = 7 Solution follows

#### Explanation:

From the formula, we can see that the number of oxygen atoms would be 4 + x. The total mass of this oxygen would then be

In the same way, the mass of the entire compound can be expressed in terms of x, as

The fraction of the mass that is oxygen is therefore

and because we know the oxygen represents 71.4% of the mass, we can write

Now, solve for x: