[heidi]

Hi there

I got stuck with this problem, and am not sure what is the best solution...

⅛ S8(s) + H2(g) → H2S(g)  delta H = -20,2 kJ·mol−1

What is delta H when 25,6 g of S8 reacts?

1)I was wondering if I am supposed to multiply the equation by 8, or not and why?
2)If I had O2 instead of S8 would the procedure be the same?

thx a lot

[constant thinker]

As far as one goes. I personally would multiply by 8, it will make your life easier. It's technically not necessary though. From there figure out the number moles you have in 25.6g of S₈. Then you can figure out how much of your product will form and subsequently the ΔH.

The procedure would be similar if you had O₂ also.

Try what I outlined. I'm assuming you know certain things. If you still have a more specific question ask.