[hipbear]

I am having difficulty figuring out the following calculation.  I know I may have to reverse and then multiply, but unsure.

Use Hess’s law to calculate delta H for:  3C(s) +2Fe2O3(s) --> 4Fe(s) +3CO2(g)   
       given:   
   
       2Fe(s) +3/2O2(g) -->Fe2O3(s)   delta H = -49.0kJ
       C(s) + O2(g) --> CO2(g)   delta H = -395kJ

Any help would be appreciated!

[Schrödinger]

I am having difficulty figuring out the following calculation.  I know I may have to reverse and then multiply, but unsure.

Use Hess’s law to calculate delta H for:  3C(s) +2Fe2O3(s) --> 4Fe(s) +3CO2(g)   
       given:   
   
       2Fe(s) +3/2O2(g) -->Fe2O3(s)   delta H = -49.0kJ
       C(s) + O2(g) --> CO2(g)   delta H = -395kJ

Any help would be appreciated!

Yes, you do have to reverse and multiply. Just think of how to eliminate those compounds that don't figure in the final balanced net equation.