Experiment 10

SPECIFIC HEAT

PROCEDURE

1.    Open up the Heat Capacity Workbook and fill in the header information. SI units will be used throughout this experiment. Express mass in kilograms, energy in joules and temperature change in C°.

2.    Spread a paper towel out on the aluminum tray.  Remove the lead shot from the container and spread it out on the tray to get it as dry as possible.

3.    Determine the mass of the empty boiler cup on the laboratory balance and then add about 400 grams of dry lead shot to the cup. Record the mass of the metal mm in cell C8 on the Worksheet.

4.    Insert the thermometer well into the metal shot and place the cup and shot into the boiler and start heating the boiler. The boiler tank should be about half full of water.

5.    While the boiler is heating, determine and record the mass of the inner calorimeter cup in cell C9 (without the insulating ring) plus the mass of the stirrer in cell C10. Record the total of cup plus stirrer as mcs in cell C11. Also note and record the type of metal (either chrome-plated brass or aluminum) that the cup and stirrer are made of in cell G9 on the Worksheet. Your lab Instructor will provide you with the specific heat of this material to enter in cell F12.

6.    Fill the calorimeter cup about two-thirds full of cold tap water, and weigh the cup, stirrer and water together. Record this value as mtot in cell C14 so that the mass of the water alone mw can be determined by subtraction and entered in cell C15.

7.    Place the calorimeter cup with the water and stirrer into the calorimeter jacket and put on the lid. Insert the thermometer into the hole so that its end is well immersed in the water.

8.     After the water in the boiler comes to boiling, and the thermometer in the metal has stabilized (this can take several minutes), record the temperature of the hot metal shot as Th in cell D18. Stir the water in the calorimeter cup gently and record the temperature of the cold water plus cup plus stirrer as Tc in cell D19. In order to get good results, the latter temperature should be several degrees below room temperature.

9.    Remove the thermometer from the hot metal shot. Remove the calorimeter lid and then quickly but carefully lift the cup containing the hot shot from the double boiler and pour the metal shot into the calorimeter cup with as little splashing as possible, so as not to lose any water.

10.    Replace the lid with the thermometer and stir the mixture slowly. The thermometer should not touch the metal shot. While stirring, watch the thermometer and record the temperature when a steady equilibrium is reached as Tf. Record this value in cell D20 on the Worksheet.

11.    Place a dry paper towel into the aluminum tray.  Dump the shot on to the paper, and dry the shot thoroughly before replacing it into the container.

12. Print out the Worksheet and use it to develop your lab report.