A compound is found to contain 50.05% sulfur and 49.95% oxygen by mass. What is the empirical formula for this compound?

What is the empirical mass of that compound? Answer using four significant figures.

C. SO2

64.07 on edge

The empirical formula is SO₂. The empirical formula mass is 64.06 u.

Assume that you have 100 g of the compound.

Then you have 50.05 g S and 49.95 g O.

Now, we must convert these masses to moles and find their ratios.

From here on, I like to summarize the calculations in a table.

Element Mass/g Moles Ratio Integers

S 50.05 1.5611 1 1

O 49.95 3.1219 1.9997 2

The empirical formula is SO₂.

EF mass = (32.06 + 2*16.00) u = 64.06 u.