Question

What is the empirical formula for a compound if a sample contains 1.0 g of S and 1.5 g of O?

Answer 1

Moles S = 1/32
Moles O₂ = 1.5/32

simplest ratio = 1 : 1.5
= 2:3

Thus, empirical formula:
S₂O₃
The fourth option is correct.

Answer 2

S atom is twice as heavy as an oxygen atom ( O is 16 and S is 32)
let's assume that 1 Arbitrary unit of sulfur is 1g heavy. this would mean that 2 units of Oxygen is 1g heavy(since it's half as heavy as S when comparing equal number of atoms). since we have 1.5g of oxygen, so there are 1.5*2=3 units of oxygen in that sample. and there are 1*1=1 units of Sulfur in that sample.
therefore the empirical formula is SO3