Purpose:To show that the volume of the gas or mixture of gases such as air, changes when the gas is heated or cooled.
Materials: Thermometer, (1) 600 ml beaker, (1) battery jar, and (1) 125 Erlenmeyer Flask, (1) stopper with a 2 in. piece of glass, glove, ring stand
Procedure: Set up an Erlenmeyer Flask with a stopper and 2-inch piece of glass tubing inserted in the stopper.
Boil approximately 400 mL of water by allowing a clamp to press on the top of the stopper. After about 5 minutes the air in the flask will be at a temperature of the boiling water approximately (100 C). When you think you have reached this point, proceed further, but first check the exact temperature of the water and record to the nearest 0.1 C.
With your finger firmly over the end of the glass tube (to prevent air from entering the flask) invert the flask into a 1,000 mL beaker of battery jar of ice water. When the neck of the flask is completely submerged, remove your finger, but keep the flask from tipping over in the water as you proceed to cover the entire flask with ice water. Allow the flask to cool completely. After approximately 5 minutes, the temperature of the air in the flask will be equal to that of the ice water (0 C). Check the exact temperature of the ice water with a thermometer. Observe the contents of the flask.
Before removing the flask from the ice water, be sure the pressure of the air inside the flask equals the pressure of the air in the room. To do this, equalize the levels of the water inside and outside the flask by raising the flask. Hold this position for three minutes. Now place your finger over the tube end, remove the flask from the bottom of the jar. Place the flask right side up on the table. You may now take your finger off the tube end.
Using a graduated cylinder, measure the volume of water in the flask to the nearest 0.12 mL. Now refill the flask with tap water. Fill all the way to the top and gently replace the stopper assembly to force out excess water. Remove the stopper assembly and measure the volume of the flask by measuring the water in it. This quantity represents the volume of hot air that was in the flask.