Download Charles` Law Lab

Honors Chemistry
Name
Chapter 13: Charles’ Law Lab
Date _____/_____/_____
Period _____
Purpose:
The purpose of this experiment is to clarify the relationships between volume, temperature, and
pressure and to test the validity of Charles’ Law by completing calculations with the collected
data. A quantity of air at about 100 oC will be cooled to a temperature of about 0 oC. The
experimentally determined volume change will be compared with V 2 and predicted
mathematically by Charles’ Law.
Procedure:
1. Arrange the apparatus as demonstrated in class. Draw a diagram below of how you are to
hold the Erlenmeyer flask during the temperature change. This diagram will need to be in your
laboratory write-up.
Use a wax pencil to mark the position of the bottom of the rubber stopper for later use in the
experiment. Immerse the dry flask assembly up to the neck of the Erlenmeyer flask in the water
and heat to boiling. Allow the flask to stand in the boiling water for approximately 8 minutes.
Record the temperature of the boiling water, T1.
2. Press your finger firmly over the glass tube and remove the flask from the boiling water. This
can be done without getting burned if you hold on to the rubber stopper. Invert the Erlenmeyer
flask into the sink that is filled with below room temperature water. Make sure that the flask is
completely submerged. After about 1 minute, release your finger and observe what happens.
Be sure to keep holding the flask under the surface.
3. Record the temperature of the cold water bath, T2. When no further changes are observed
raise the flask so that the water level inside the flask coincides with the water level outside,
while keeping the glass tube under the water. Remove the flask by again covering the glass
tube with your finger. Stand the flask upright on your bench. Dry the outside of the flask and
measure the volume of water inside the flask by pouring the water into a 100 mL graduated
cylinder. Record the volume as Vw. After completing this measurement, fill the used flask with
water to the wax pencil line and measure the water by pouring it into the 250 mL graduated
cylinder. If all of the water does not fit, record and repeat. This recorded volume is V 1.
Data:
(Trial 1)
(Trial 2)
(Trial 3)
1. T1 of the gas (Hot water Bath)
= _________K
_________K
_________K
2. T2 of the gas (Cold Water Bath)
= _________K
_________K
_________K
3. Vw (Volume of the water that
entered the flask)
= _________mL
_________mL
_________mL
4. V1 (Total Volume of the Flask)
= _________mL
_________mL
_________mL
5. V2 = (V1 – Vw)
= _________mL
_________mL
_________mL
Calculations:
1. Using Charles’ Law, calculate the theoretical second volume, V2 theoretical.
2. Calculate the percent error.
Questions: (Complete the following questions on a separate piece of paper.)
1. As the air inside the flask is heated, what is happening to its volume?
2. What happened after your finger was released? Why did this occur?
3. What is the relationship between the volume of water entering the flask and the decrease
in volume of the air inside the flask as it cooled.
4. What was the reason for making the water levels coincide before putting your finger over
the tube and removing the flask from the water?
5. What is the gas used in this experiment?
6. State Charles’ Law in words.
7. Since the cooled gas was collected “over water”, Dalton’s Law of Partial Pressure must
be applied. A pressure correction is determined by subtracting the water vapor pressure
from the atmospheric pressure to get P2 while atmospheric pressure is used as P1. Using
this information, calculate the theoretical V2 for the experiment using the ideal gas law for
two gases.
8. Is the theoretical V2 calculated using the ideal gas law any closer to the experimental V2
than the V2 calculated using Charles’ Law? Explain why or why not.
9. Calculate the percent error for theoretic V2 calculated using the ideal gas law..