Zinc reacting with oxygen - IS THIS RELATION CORRECT?

[aero_zeppelin]

Homework Statement

Powdered zinc is heated with sulfur to form zinc sulfide... however, part of the reactants react with O2 as well and form zinc oxide and sulfur dioxide...

Imagine that 85.2 g of Zn reacted with 52.4 g of S8 and 105.4 g of ZnS was formed...

If the remainder of the reactants combined with O2 to form zinc oxide and sulfur dioxide, how many grams of zinc oxide formed??

Homework Equations

8 Zn + S8 --> 8 ZnS Balanced equation

The Attempt at a Solution

Ok, so I think I have this problem figured out, but I just want to know if the next relation is right...

I'm using a rule of 3 to find the mass of Zinc that's "missing"

97.45 g of ZnS ----- 65.38 g Zn
105.4 g of ZnS----- x

So basically, what I'm saying is: If 97.45 grams of ZnS (molar mass of zinc sulfide) contain 65.38 g of Zn (molar mass of Zn), then how many grams of Zinc are there in 105.4 of ZnS?
I'm obtaining 70.71 g of Zn, then substracted this from 85.2 g and going from there...

I just want to know if this relation is correct... the rest of the problem is all figured out... The question actually suggests using percent yield data, but I used this method instead...

If this is wrong... I'd appreciate some advice... the percent yield from the previous exercise was 83%

Thanks a bunch!

 

[Borek]

Looks OK to me.

 

[aero_zeppelin]

great, thanks!