Given the following reactions and subsequent ∆h values what is the ∆h for the reaction below? 4co2 (g) 2h2o (g) 2c2h2 (g) 5o2 (g)

You do these problems by finding the heat of formation of each compound, from a table.

Then the heat of reaction is the (sum of the heats of formation of the products) minus (sum of the heats of formation of the reactants).

In your case, the ∆Hrxn = 5∆Hf (O2 (g)) + 2∆Hf (C2H2 (g)) - 2∆Hf (H2O (g)) - 4∆Hf (CO2 (g)).