What is the empirical formula for a compound which contains 67.1% zinc and the rest is oxygen?

1 Answer
Dec 19, 2016

ZnO2

Explanation:

With all these problems, we assume that there are 100g of unknown compound, and then we proceed to calculate the empirical formula:

Moles of zinc = 67.1g65.4gmol1=1.03mol

Moles of oxygen = 32.9g15.999gmol1=2.06mol

Given the molar ratios, we divide thru by the lowest molar quantity to get an empirical formula of ZnO2. The examiner has been nasty in that the expectation would have been ZnO. However, zinc does form a peroxo species composed of Zn2+ and O22 ions.