Since mass is always conserved which means that what goes in the process should be the same as what goes out. You should only have one product, the lead oxide must be made up of 0.500 g tin and 0.135 g oxygen
The atomic mass of tin is 118.71 g and the atomic mass of oxygen is 16 g
We calculate the number of moles of each element in the product as follows:
Sn = 0.5 /118.71 = 0.004212
O = 0.135/16 = 0.00844
Then, we find the ratio between the elements,
Sn = 0.004212/ 0.004212 = 1
O = 0.00844 / 0.004212 = 2
Therefore, the empirical formula must be SnO2.