In this experiment, you will use a coffee cup calorimeter, consisting of a double styrofoam cup and a plastic top with a hole for a thermometer. The use of a calorimeter is detailed in the ChemLab website, both in the Techniques section and in the Overview pages for this week's experiment. In addition to using the calorimeter properly, key techniques for obtaining accurate results are starting with a dry calorimeter, measuring solution volumes precisely, and determining T accurately.
Careful experimenters deal with the first two items easily.
The last is somewhat more difficult. The determination of a precise value for T 2 is complicated by the fact that a small heat exchange occurs between the surroundings and the contents of the calorimeter, both during the reaction and after its completion. The rate of exchange depends on the insulating properties of the calorimeter and on the rate of stirring. The value of T 2 obtained in this manner is the temperature of the product solution, had the reaction occurred instantaneously with no enthalpy loss to the surroundings. It is good practice to plot temperature vs. time in your notebook as you record the data, during the experiment.