# Homework Help: Sulfur problem

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1. Dec 3, 2015

• Please post this type of questions in HW section using the template.
A sample of sulfur having a mass of 1.28 g combines with oxygen to form a compound with a mass of 3.2g. What is the empirical formula.
So what i did is found the mass of oxygen which is 1.92g . Then converted the 1.28g S to 0.04 mol. Then converted the 1.92g O2 (as it says oxygen, or should it be just O?) to get 0.24mol O. I found online that the answer should be SO3, but I get SO6 because of Oxygen. Should I not assume it is diatomic, and just go with as just element?

2. Dec 3, 2015

### SteamKing

Staff Emeritus
When the oxygen is combined with another element in a compound, it is no longer in diatomic form. Plus, there's no such compound as SO6, AFAIK, unless the valence of S is 12 instead of 2.

3. Dec 3, 2015

So when it says that oxygen is combining it should be just O, not O2. If i understood correctly.

4. Dec 3, 2015

### rootone

Yes a single oxygen atom has combined with some other element(s).
It may or may not have originally been an atom which was existing previously as part of diatomic oxygen.