Experiment: Bomb Calorimetry


    The heat change associated with the combustion of a compound, such as CwHxNyOz , is measured with a bomb calormeter.

CwHxNyOz (s)   +   ( 2w + x/2 - z)/2 O2 (g)     — ›     w CO2 (g)   +   x/2 H2O (l)   +   y/2 N2 (g)

    The experimental procedure used to acquire the heat change is illustrated in the JAVA applet below. Select a compound (benzoic acid, glycine, naphthalene, oxalic acid, and sucrose) to be burned, enter the weight of the sample of the selected compound, and click the "Start" button. When the "Ignite" button appears, click the button to initiate the combustion reaction. Record the intial and final temperatures of the calorimeter. See the Tutorial for Experiment: Bomb Calorimetry for an example and help.

Compound Chemical Formula Molar Mass (g/mole)
benzoic acid C7H6O2 122.12
glycine C2H5NO2 75.07
naphthalene C10H8 128.17
oxalic acid C2H2O4 90.04
sucrose C12H22O11 342.30

    Place a 3.300 g sample of benzoic acid in the bomb. After the calorimeter is assembled, ignite the sample and record the initial and final temperatures.

  1. If DEcomb = -26.43 kJ/g for benzoic acid , how much heat will be produced when 3.300 g of benzoic acid are burned in the calorimeter?
  2. Why does the temperature of the water in the bucket rise?
  3. If the specific heat capacity of water is 4.180 J/g-oC, how much heat did the 2000 g of water absorb?
  4. Why is the amount of heat absorbed by the water not equal to the amount of heat produced from the combustion of the 3.300 g sample of benzoic acid?
  5. Calculate the heat capacity of thecalorimeter, Ccalor. See the lecture notes for help.

    If you have preformed all of the experiments, answered all of the questions above, and completed this section of the report to be submitted for credit, then you may check the Answers to the First Set of Questions



    Place a 2.000 g sample of naphthalene in the bomb. After the calorimeter is assembled, ignite the sample and record the initial and final temperatures.
  1. How much heat is produced when the 2.000 g sample of naphthalene is burned?
  2. Calculate DEocomb for the combustion of 1.00 mole of naphthalene.
  3. Calculate DHocomb for the combustion of 1.00 mole of naphthalene. See the lecture notes for help.
  4. Calculate DHof for naphthalene. See the lecture notes for help.

    If you have preformed all of the experiments, answered all of the questions, and completed the report to be submitted for credit, then you may check the Answers to the Second Set of Questions



Nutt 99




Dr. Nutt's CHE 115 Course