Suppose we had mixed 52.37 mL of 1.00 M HI solution with 25.42 mL of 1.00 M KOH solution, and measured a heat of reaction of -1.52 kJ. What is ΔH for this reaction, in kJ? Assume that all solutions have the same density as water (1.00 g/mL).

Answer 1

HI + KOH ==>KI + H2O
mols HI = M x L = ?
mols KOH = M x L = ?
One of them will be the limiting reagent; i.e., the one with the smaller mols. That will give you the mols of H2O produced.
You know q is 1.52 kJ and that is dHrxn. USUALLY you want kJ/mol. Then dHrxn/mols H2O will give that to you.