# Thermodynamics problem?

How do i solve this chem, thermodynamics problem?
find ΔHf for OH(g) if

H2O2 (g)--> 2OH(g)

ΔH(diss)=213KJ/mol

what is ΔH(diss)?? what is 'diss'

someone told me The ΔH(diss)=213KJ/mol is equal to twice the ΔHf of OH. but i doont know how they got to this, also it seems a bit too simple for a qestion if all i need to do is divide by 2,
so how would i solve this?

Your $$\Delta H(diss)$$ is your enthalpy of reaction. Remember that the enthalpy of reaction equals: Enthalpy of formation of products - Enthalpy of formation of reactants. Replace your data (you will need to look for H2O2 enthalpy of formation on a table) there and solve for $$\Delta H(OH)$$.