Use the thermochemical equations shown below to determine

Question

the enthalpy (kJ) for the reaction:

H2SO3(l)=>H2S(g) + 3/2O2(g)

H2SO3(l)=>H2O(l) +SO2(g) DH=62KJ

SO2(g)=>S(s) + O2(g) DH=297KJ

H2S(g) +1/2O2(g)=>S(s) + H2O(l) DH=-155KJ

so you just add 62kj +297kg+155kj
to get 514. That seems easy enough

Answer 1

Your target equation is not apparent from your post; however, if the target equation is the first one in the post, adding the other three will not get the equation you want.

Answer 2

well can you help me. I have to do other problems similar to this and i've been looking it up in my book and online and cant seem to get the hang of how to do it.

Answer 3

Label the equation you have as 1, 2, 3.
Use equation 1 as is.
Use equation 2 as is.
Reverse equation 3 (change the sign of DH when you reverse an equation), than add all of them and the new DHs. Check to make sure the equation is what you wnat, the It will be DH(1) + DH(2) + (-DH)(3)

Answer 4

That last line I wrote could be confusing. You add the three NEW equations as outlined above. Then you add the three NEW DHs (the equation 1 DH as is, the equation 2 DH as is, and the NEW DH for equation 3.)