moved into the flask from the total volume of the flask. This is the volume of the gas inside the flask after cooling.
20. Your data table should look something like this:
Data Points
Temperature in Celsius
1( record temperature of the flask in the boiling water)
2( record temperature of the ice bath)
Volume in mL
( total volume of flask)
( total volume of flask minus volume of water that moved in)
21. On your graph, temperature should be on the x-axis. The range of temperatures should be from-300 to about 150 degrees C. Volume in mL should be on your y-axis. The range of volumes should be from 150 mL to 0 mL.
22. Plot your two points.
23. Using your ruler, draw a straight line between them.
24. Line up your ruler with the line you already started. Make a dotted line extending the line you drew all the way to where the volume is equal to 0 on the x-axis.
25. Carefully determine the temperature, where your line crosses the X axis. This is your determination of absolute zero!
Results
The expected value for absolute zero is-273.15 C. If your value falls between-250 C and-300, you did well considering the limitations of your equipment and graph paper.
Volume
Temperature( K)
Why?
SCIENCE PROJECT
WINSPIRE: Empowering youth | December, 2016
29
Materials required
All the glass materials must be made of some sort of Pyrex-like material, to prevent shattering during temperature changes.
• Bucket • Ice • Big spoon
• Water • Safety goggles
• 125 mL Erlenmeyer flask
• Large beaker, at least 500 mL
• One-hole rubber stopper that fits the 125 mL flask
• Short glass rod( 5- 10 cm) that fits snuggly into the stopper hole
• Ring stand • Clamp • Hot plate
• Tongs big enough to hold the 125 mL flask • Celsius thermomete
• Graduated cylinder • Graph paper
• Ruler
• As you cooled the flask in the ice bath, the molecules of gas inside the flask moved around less and less. The gas molecules took up less space inside the flask, so water from the outside slowly moved in. Charles’ law predicts that as the temperature decreases, the volume also decreases.
• Another important concept related to gases, pressure and temperature is Gay-Lussac’ s Law: the pressure of a fixed mass of a gas at a constant temperature varies directly with the temperature. The
P equation for this relationship is =
2
T 1
T. 2
You might remember that the pressure of a gas is the amount of force exerts per unit of surface. An example of this phenomenon is when the lid of a plastic container pops off when you heat it in a microwave. The temperature is going up, but the volume of the gas remains the same because the lid. Pressure therefore increases with temperature until it is high enough to pop open the lid.
P 1