Calculate the standard enthalpy change, ΔH° for the following reaction:

6NO(g) + 6SO2(g) → 3N2(g) + 6SO3(g)

Equations: ΔH°rxn (kJ)
SO2(g) + NO2(g) → SO3(g) + NO(g) -42.7
1/2N2(g) + O2(g) → NO2(g) 33.8
SO2(g) + 1/2O2(g) → SO3(g) -99.2

Question

Calculate the standard enthalpy change, ΔH° for the following reaction:

6NO(g) + 6SO2(g) → 3N2(g) + 6SO3(g)

Equations:	     	                            ΔH°rxn (kJ)
SO2(g) + NO2(g) → SO3(g) + NO(g)	     	-42.7
1/2N2(g) + O2(g) → NO2(g)	     	          33.8
SO2(g) + 1/2O2(g) → SO3(g)	     	        -99.2

wolfe8 · Answer

A way to do that is to manipulate(multiply by scalar) the equations and add them together so in the end you get the equation you want for the reaction. Note that if you reverse an equation, you change the sign for the delta H