A Watched Pot Never Boils

This is my variation of the real life experiment that has been performed for years to determine much of the information (boiling point, freezing point, heat of fusion, heat of vaporization, specific heat capacity, DTE) we know about different materials.

Materials:

beaker (400 mL) graduated cylinder

large test tube water

hot plate ice

triple beam balance

temperature probe

Procedure:

1. Gather all materials. Make sure the temperature is plugged in to port #1 on the blue module. Open the “VID2 EXP” file on your computer as instructed by your teacher. Turn the heat dial of the hot plate to the number 10.

2. Place the large test tube in the beaker. Measure and record the mass of the beaker+test tube combination.

3. Put ice in the test tube until the ice is about 5 cm deep. Measure and record the mass of the beaker+test tube+ice combination.

4. Add about 5 mL of water to the test tube. Measure and record the mass of the beaker(+test tube+ice) combination.

5. Place the temperature probe in the test tube. Start the temperature probe by clicking on the green “G” in the toolbar. You will need to hold the temperature probe so that the tip stays in the top centimeter of the ice water.

6. When the time on the temperature program reaches 30 seconds place the beaker on the center of the hot plate surface. Be careful that the probe wire does not make contact with the hot plate surface. Be sure to hold the temperature probe so that the tip stays in the top centimeter of the ice water. The main thing is to measure the temperature of the ice as it melts. Once all the ice has melted you can let the temperature probe rest in the test tube.

7. Record the time when you first see some condensation on the upper part of the test tube.

8. Record the time when you first see some fog rising out of the test tube.

9. When the computer probe stops collecting data (~26 min) turn the hot plate off and remove the temperature probe.

10. Save your data as “vid2” in your class period folder.

11. Allow the beaker to cool for 5 minutes.

12. Measure and record the mass of the beaker+test tube+water.

13. Clean and dry the material and return all materials.

Analysis:

You will need the following information for water to complete the analysis: specific heat capacity, heat of fusion, and heat of vaporization.

1. How much ice water (mass) was in your test tube?

2. How much time did it take for the water to heat up from 0 °C to 100 °? How much energy was needed to heat the water to the boiling point?

3. Based on this information determine the energy provided by the hot plate each second.

Use the answer to #3 to help answer the following:

4. How much energy was needed to melt all the ice?

5. How much energy was used while the water was boiling?

6. How much water (mass) was lost due to the heating?

7. Sketch the graph of your data. Label the three main parts of the graph.