What is the empirical formula for a compound that is 33.36% calcium, 26.69% sulfur, and 40.00% oxygen?

1 Answer
Feb 2, 2017

The empirical formula is CaSO3.

Explanation:

1: We have to do is assume 100g.

Therefore:
- Calcium: 33.36%33.36g
- Sulfur: 26.69%26.69g
- Oxygen: 40.00%40.00g

We do this because the percent is in relation to 100%. By assuming 100%, all the values can be viewed as values in grams.

2: We find the mols of each element.

Now that we have the mass, the molar mass is the individual molar mass of each element.

nC=mM

=33.3640.08

=0.832335329

nS=mM

=26.6932.07

=0.83224197

nO=mM

=40.0016.00

=2.5

3: Now we take the lowest value of mols and divide every other mol by that.

Calcium has the smallest mol: 0.832335329

Calcium:

=0.8323353290.832335329

=1

Sulfur:

=0.832241970.832335329

=1

Oxygen:

=2.50.832335329

=3

Therefore, the empirical formula is CaSO3.