Experiment 3. Bomb Calorimetry The picture here shows the Parr bomb calorimeter that is illustrated schematically on p. 153 of the lab text. The bomb is illustrated in more detail on the next page. After it is prepared, it is inserted into the pail, along with 2.00 L of water. Then the lid is installed. It contains the stirring assembly and a hole for inserting the thermometer or (in our case) thermistor. The adiabatic jacket reduces but does not completely eliminate heat flow between the contents and the environment, which is why we must use extrapolation procedures.

2 The bomb is illustrated schematically on p. 154 of the lab text. The instructor will take you through the preparation of the bomb for your first run. It is important for both success and safety that this be done correctly. Perhaps the biggest source of failure in this experiment is improper connection of the fuse wire to the electrodes, or poor contact between the wire and the pellet, so take special care here. We have never had an actual explosion of a “bomb.” Please don’t become our first!

3 One of our biggest sources of frustration in connection with this experiment is students leaving chemical “crumbs” in the work area near the balances. Your pellets will mostly already be of a size suitable for use in the experiment, but if you do need to reduce their size, remember to clean up and properly dispose of any shavings. A REAL NO-NO! As always, be considerate of your fellow scholars!