How do I solve this AP Chemistry problem?

Question

1/2O2 (g)+ Hg (l)====> HgO (s) ΔH= -90.8 kJ. How do I calculate how much heat is released when 42.5g of By is reacted with oxygen

Answer 1

I see you are listing a series of questions, so instead of doing them all for you, I'll guide you. Hope that's ok.

 

You probably mean ...when 42.5 g Hg (not By) is reacted with oxygen.

 

1/2O₂(g) + Hg(l) ==> HgO  balanced equation.

Again, as in a previous question/answer, you know that 90.8 kJ of heat are generated when 1 mole of Hg(l) reacts with oxygen.  So, figure out how many moles of Hg you have when you have 42.5 g and then you can calculate the heat from that much Hg.