4B10.29 - Dulong - Petit Law of Specific Heat

See paragraph two in the procedure section
Code Number:
Demo Title:
Dulong - Petit Law of Specific Heat
Measuring the specific heat of solids
Area of Study:
Heat & Fluids
2 calorimeters with 40 ml of water in each, computer interface with thermometers in channels A and B, Bunsen burner, 1000 ml beaker with stand, tongs.

The Dulong-Petit Law states that in particular the metallic elements have approximately the same Molar heat capacity.  This is approximately 
25 J/mol-deg.  

 For our experiment we take 1/2 mole of aluminum (13.5g) and 1/2 mole of lead (103.5g) and bring them to the same temperature in boiling water.  Take out the metal canister part of the calorimeter and replace it with the Styrofoam cup inserts.  Place 40 ml of water in each calorimeter which should have a starting temperature of about 22 degrees C (room temperature).  When the samples are dropped into the calorimeter each should show approximately a 5 degree C temperature increase showing that the same number of moles of a metal will give the same temperature increase.  

HINT:  To keep the sample from touching the thermometer when you drop it into the calorimeter, tilt the calorimeter so the sample drops away from the thermometer. 

  • Ronald F. Gleeson,  "A Sequel to the PSNS Specific Heat Experiment",  TPT, Vol. 10, # 7, p. 399, Oct. 1972.
  • E. Lagendijk, "A Simple Determination of the Einstein Temperature", AJP, Vol. 68, # 10, p. 961, Oct. 2000.
  • John Henry Pepper, "Capacity for Heat", Cyclopadic Science Simplified, p. 164. 
  • Arthur B. Ellis, Margret J. Geselbracht, Brian J. Johnson, George C. Lisensky, William R. Robinson,  "Indirect Evidence for Atoms:  Heat Capacities",  Teaching General Chemistry - A Materials Science Companion,  p. 24.

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