Question

There are two binary compounds of mercury and oxygen. Heating either of them results in the decomposition of the compound, with oxygen gas escaping into the atmosphere while leaving a residue of pure mercury. Heating 0.6498 g of one of the compounds leaves a residue of 0.6018 g. Heating 0.4172 g of the other compound results in a mass loss of 0.016 g. Determine the empirical formula of each compound.

Answer 1

For the first compound the ratio of mercury to oxygen is

0.6498 : 0.048

dividing these values by the molar masses of Hg and O:
06498/200.6 : 0.048 / 16
= 0.003 : 0.003
= 1 : 1

so empirical formula for first compound is HgO

Answer 2

You can solve the second part in the same way