Charles’ Law Lab
Prelab – You will need to complete the following in your lab book - title, purpose,
background information, storyboard of the procedures, and develop a data table for
the lab.
INTRODUCTION
According to the kinetic theory, an increase in temperature will cause the molecules of a gas to
move faster and exert more pressure, or cause the gas to expand. Conversely, as a gas is cooled,
the molecules will move more slowly and the gas will contract, or exert less pressure. In other words,
the volume of a gas increases as temperature increases if the pressure remains constant. This
relationship between the volume of a gas and its temperature is known as CHARLES’ LAW.
PROCEDURE
1. Prepare a data table for the experiment that includes the following information: temperature of
boiling water (T1), Temperature of the water in the sink (T2), Volume of the water in the cooled
flask, volume of the water that fills the flask (V1).
2. Set up the apparatus as shown here (sketch this in your storyboard)
Obtain a 600 mL beaker and add approximately enough tap water to completely cover the
immersed 250 mL flask. Obtain a dry 250 mL Erlenmeyer flask. Place a one-hole stopper,
size 5 or 6, fitted with a glass dropper pipet into the flask, and place the flask into the beaker
of water as shown. Heat the water to boiling and measure the temperature using the
thermometer. Record the temperature of the boiling water in your data table. Continue
heating at this temperature for at least 3-5 minutes. Lower the heat if necessary to minimize
splattering. There will be some splattering so move your books and papers out of the way.
What is happening to the gas in the flask during this process?
3. While the flask is heating, prepare the sink by placing a stopper in the drain and filling it with
water (up to about 1 inch from the top of the sink).
4. Push your sleeves up so that they do not get wet in step 5. Remove the hot flask from the
beaker. Protect your hand while placing your finger firmly over the end of the glass pipet (this
should not be hot, but THE FLASK ITSELF WILL BE HOT).
5. Submerge the flask in the sink keeping it perpendicular to the desktop. Do not allow air to
enter the flask while transferring it to the sink by keeping your finger securely over the entire
glass pipet. Once the flask is in the water you can remove your finger from the pipet and
should remove the clamp, but be careful because it and the flask may still be HOT. Also be
careful not to tilt the flask too much past perpendicular.
6. Hold the flask under the water (with the open pipet facing down) until the flask has cooled and
the water stops entering. Raise the flask, while keeping it perpendicular, with the glass tube
still facing down, until the water level inside the flask is the same as the water level outside the
flask. The pressure inside the flask is now equal to atmospheric pressure outside the flask.
7. Place your hand underwater while the two water levels are equal and put your finger over the
glass tube. Carefully remove the flask from the water trapping all of the water inside the flask.
Place the flask in an upright position on your lab table and then remove your finger. What
happened to the volume of the gas? How can you tell?
8. Using a wax pencil, make a mark on the flask at the bottom of the rubber stopper. You may
now take the stopper out. Measure the temperature of the water in the sink and record the
temperature as T2.
9. Pour the water in the flask into a graduated cylinder and record the volume in your data table
as the volume of the water in the cooled flask. Think about what this water volume will allow
you to calculate.
10. Fill the flask to the line you marked at the bottom of the stopper. Measure the volume of this
water in a graduated cylinder and record it as the volume of water that fills the flask. Think
about what this volume will tell you.
Post lab activities 
Calculations - For each of the following give a word equation and show all of your work.
1. Convert both temperatures to Kelvin.
2. What is the initial volume of the gas? (hint: there is no calculation needed here) Be sure to
explain how you know that this is the volume of the gas.
3. Calculate the experimental volume of the gas in the flask after it has cooled.
4. Use Charles’ Law to determine the theoretical value for V2 using the measurements you took
for V1, T1, and T2.
5. Calculate the % error of your experimental value for V2.

Conclusions – Address specific possible reasons for your errors