Question #05d76

1 Answer
Dec 16, 2016

The empirical formula is As2O5.

Explanation:

As with all these problems, we ASSUME that there are 100g of unknown compound.

Given the elemental percentages, thus there are:

Moles of oxygen = 34.8g15.999gmol1=2.18mol.

Moles of arsenick = 65.2g74.9gmol1=0.871mol.

We divide thru by the smallest molar quantity to get, O:As, 2.5:1.0.

But by definition, the empirical formula is the simplest WHOLE number ratio that defines constituent atoms in a species, so we take this preliminary determination, and DOUBLE it to give WHOLE numbers:

As2O5. Capisce?