Experiment 1: Properties of Water
1. Take a constant temperature bath from the Instruments shelf and place it on the workbench.
2. Set the constant temperature bath to the freezing temperature of Ethylene Glycol (-15.0 °C).
3. Take a clean test tube from the Containers shelf and place it on the workbench.
4. Fill the test tube with 10 mL of water.
5. Take a thermometer from the Instruments shelf and attach it to the test tube.
6. Take the test tube and place it in the constant temperature bath.
7. Watch the test tube and thermometercarefully. As the water freezes at 0°C, you will see ice form in the test tube and the temperature of the ice/water mixture will remain constant. This is the freezing/melting point of water. Once all of thewater has frozen, the solid ice will be further cooled and your will see the temperature drop.
(You may want to use the + or – zoom buttons in the lower right of the screen for a closer view.)
8. Take a bunsen burner from the Instruments shelf and place it on the workbench.
9. Take another clean test tube from the Containers shelf and place it on the workbench.
10. Fill the test tube with 10 mL of water.
11. Take a thermometer from the Instruments shelf and attach it to the test tube.
12. Place the test tube, with the thermometer still attached, on the bunsen burner.
13. Turn on the bunsen burner by clicking on the black knob. The initial setting is the low flame which you will use now.
14. Watch the test tube and thermometercarefully. When the water begins to boil at 100°C, the temperature will remain constant as liquid water is converted to steam. You will also see vapor escaping from the open test tube. This is the boiling point of water.
15. Turn off the bunsen burner.
16. Discard the test tubes by dragging it to the recycling bin under the workbench.
Experiment 2: Properties of Unknown Liquids
1. You will now repeat the procedures to determine the melting and boiling points for four unknown substances. In their liquid phase, they look like water and are hard to tell apart. However, their characteristic melting and boiling points will allow you to identify them.
2. Take two clean test tubes from the Containers shelf and place it on the workbench. Fill each with 10 mL of the Liquid #1 from the Materials shelf..
3. Take thermometers from the Instruments shelf and attach one to each test tube. Make sure that they connect to the test tube and display room temperature (21.5 °C).
4. Measure the melting temperature of the liquid as you did for water by immersing one of the test tubes in the constant temperature bath set to the freezing temperature of Ethylene Glycol (-15.0 °C) until the substance begins to freeze and the temperature remains constant. Record the freezing/melting point for the substance in your lab notes.
NOTE: If your Unknown Liquid does not freeze, it may be necessary to lower the setting to the freezing temperature of Dry Ice (-78.5 °C).
5. Measure the substance's boiling temperature by heating the second test tube over the bunsen burner until vapor appears at the top of the test tube and the temperature remains constant.
6. Record the boiling point of the substance in your Lab Notes.
7. Discard the test tubes in the recycling bin beneath the workbench.
8. Repeat this procedure for the other three unknown liquids.
9. Clean your workstation. Don’t forget to save your notes
Note: You will get lab record and latenitelabs assignment answers