enthalphy formation from enthlapy reactions

Question

A scientist measures the standard enthalpy change for the following reaction to be -605.2 kJ :

2CO(g) + O₂(g)2CO₂(g)

Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of CO₂(g) is 

Answer 1

We can't answer this without knowing the standard enthalpy of formation for CO(g). Look it up and then use

sum of products - sum of reactants = ∆Hº_rxn

You have the ∆H_rxn, and you'll have the ∆Hº for CO(g) so you can solve for ∆H CO₂(g)