A student is asked to determine the molar enthalpy of neutralization, ∆Hneut, for a reaction between a strong acid and a strong base. The student combines equal volumes of 1.0 M HCl(aq) and 1.0 M
NaOH(aq) in an open polystyrene cup calorimeter. The heat released by the reaction is determined by
using the equation q = mc∆T. Assume the following:
• Both solutions are at the same temperature before they are combined.
• The densities of all the solutions are the same as that of water.
• Any heat lost to the calorimeter or to the air is negligible.
• The specific heat capacity of the combined solutions is the same as that of water.
a) Give appropriate units for each of the terms in the equation q = mc∆T.
b) What quantitative values must be made in order to obtain the value of q?
c) The student repeats the experiment with the same equal volumes as before, but this time uses 2.0
M HCl and 2.0 M NaOH.
i. Indicate whether the value of q increases, decreases, or stays the same when compared to the
first experiment. Justify your prediction.
ii. Indicate whether the value of the molar enthalpy of neutralization, ∆Hneut, increases, decreases,
or stays the same when compared to the first experiment. Justify your prediction.
d) 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?