Chemistry Lab Essay

461 Words2 Pages
[pic] Practical 3 TOPIC : Behavior of Gases OBJECTIVE: To determine the molar mass of a vapor MATERIALS NEEDED: 1. Volatile unknown liquid 2. Distilled water 3. Rubber band 4. Bunsen burner 5. 100 mL Erlenmeyer flask 6. 250 mL graduated cylinder 7. Tripod stand 8. Wire gauze 9. Pins (needle/map pins) 10. 2-in. square of aluminium foil 11. 500 mL beaker 12. Balance 13. Thermometer PROCEDURE 1. Place a small square of aluminium foil over the mouth of a clean, dry 100 mL Erlenmeyer flask. 2. Fold the foil loosely around the neck and secure with a rubber band. 3. Make a very small hole in the center of the foil with a pin. Weigh the flask, foil cap and rubber band. 4. Place about 300 mL of water in a 500 mL beaker and begin heating to boil the water. 5. While the water is heating, remove the foil from Erlenmeyer flask and place about 2 mL of unknown liquid in the flask; then replace the foil and rubber band. 6. After the water has been brought to a boil, record its temperature. 7. Insert the Erlenmeyer flask into the boiling water. 8. After about 4 minutes, remove the flask from the boiling water and examine it to see if all the unknown liquid has vaporized. 9. If it has not, re-insert the flask into the boiling water for a few minutes. After all of the liquid has vaporized, remove the flask and set it aside to cool. 10. After the flask has cooled to room temperature, wipe it dry and remove any water that may adhere to the flask and aluminium foil. 11. Weigh the flask, cap, rubber band and condensed unknown liquid. 12. Calculate the mass of condensed liquid. 13. Remove the cap and fill the flask completely with water. 14. Measure the volume by pouring the water into 250 mL graduated cylinder. 15. Calculate the molar mass of unknown liquid using
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