Question #a6569

Apr 22, 2014

In essence, you are finding the ratio of oxygen mass to total mass.

The first step in solving this problem is to determine the molar mass of the entire substance:

Ca = 40.08
N = 14 --> multiply this by 2 because the subscript outside the brackets applies to the entire thing.
O = 16 --> multiply this by 2 (the 2 beside the O indicates this), then multiply by 2 again, indicated by the two outside the brackets.

Total Mass = 40.08 + 2(14) + 4(16)
Total Mass = 132.08

Now, you set up the ratio of ONLY oxygen to the total mass and find the answer:

$\left(64 \text{ (mass of oxygen)")/(132.08" (Total Mass)}\right)$ = $0.4845$

Now, take this decimal and multiply it by 100% to turn it into percent form: 0.4845 x 100% = 48.45%