coffee-cup calorimeter

Question

When doing an experiment using a coffee-cup calorimeter, NaOH, and Acetic Acid:

1. If some heat was lost to or gained from the surroundings what would happen to the measured ΔT?
2. How does this affect the calculated ΔH_rxn?

Answer 1

NaOH + CH3COOH ==> CH3COONa + H2O is a neutralization reaction and is exothermic. This means heat is generated by the reaction and is given off to the surroundings. If some heat was lost from the coffee cup, the ∆T would be underestimated and ∆H would be underestimated since ∆H is directly related to ∆T. Vice versa if heat was somehow gained from the surroundings.