[gsalinas_44]

Sulfur, S8, combines with oxygen at elevated temperatures to form sulfur dioxide.

           I believe that the equation is:  S8 + 8O2 ---> 8SO2
1. If 200 oxygen molecules are used up in this reaction, how many sulfur molecules are formed?

2.  How many sulfur dioxide molecules are formed in part 1?

[Bakegaku]

First of all, please read the rules and a nettiquette guide.  There's a link to the rules at the top of the page.  Typing in all capitals makes your question difficult to read (thus difficult to answer) and you should show your attempts at a problem when posting it.

As far as starting advice goes, however, I'd strongly suggest writing out the balanced equation of the combustion of S₈

[gsalinas_44]

here i believe that the equation is done by placing our equation in this from:

200molecules O2x 1 mol O2 x  6.02 x 10^23 molecules SO2 = 2 x 10^48 molecules Sulfur
                          6.02 x 10^23 molecules O2     1 mol O2 

Could any one check this out and see if it make sence.

Thanks

[Borek]

No need for moles here. Please visit stoichiometric calculations page to check how the balanced reaction can be read.

[AWK]

1. If 200 oxygen molecules are used up in this reaction, how many sulfur molecules are formed?

You mean sulfur dioxide molecule, I hope!

[DevaDevil]

I assume Pt.1 is about how many S₈ are being used up, and Pt.2 about how many SO₂ formed

Isn't it pretty straightforward then if the reaction ideed follows stoechiometry: S₈: O₂ = 1/8;
S₈ used = 200/8 = 25
and SO₂ formed is as much as oxygen used: 200 molecules.

As Borek said: Check how to read the balanced equations, then you'll find they're pretty straightforward.