Hello,
On a test, the following information preceded a question:
H+(aq) + OH-(aq) H2O(l)
A student is asked to determine the molar enthalpy of neutralization, ∆Hneut , for the reaction
represented above. The student combines equal volumes of 1.0 M HCl and 1.0 M NaOH in an open polystyrene cup calorimeter. The heat released by the reaction is determined by using the equation q = mc∆T.The last of the questions that followed asks:
Suppose that a significant amount of heat were lost to the air during the experiment. What effect would this have on the calculated value of the molar enthalpy of neutralization, ∆Hneut ? Justify your answer.I wrote, "the calculated value of ΔH
neut would increase because the heat lost to the air will cause the value of ΔT to be smaller."
This is incorrect, apparently, and the correct answer is supposed to be that ΔH
neut decreases. However, since the reaction is exothermic, would ΔH not be negative? So since the question does not ask for change in the
magnitude of ΔH, why is saying it increases incorrect?