Name: ______
Group: ______
Charles’ Law Lab
Aim:
To experimentally determine absolute zero.
Materials:
Hot plateRing stand &clampThermometer
600 ml BeakerSink plugRubber Stoppers
Glass tubingGraduated Cylinders (100ml, 500ml)
Erlenmeyer Flasks (125 ml, 250 ml)
Procedure:
1- Prepare hotplate, ring stand, and clamp by referring to the demo.
2- Fill the beaker with tap water and place on the hot plate.
3- Turn hotplate to “High” and wait for boiling.
4- Fill the sink with tap water and record the temperature. (Temp 2)
5- Once the water is boiling rapidly, record the temperature. (Temp 1)
6- Place the first flask with rubber stopper in the clamp and lower into the boiling water. DO NOT submerge the flask.
7- Wait approx. 1 minute to allow the temperature of the gas inside the flask to rise to the temperature of the water.
8- Place a finger over the glass tubing in the rubber stopper and remove the flask from the boiling water bath.
9- QUICKLY and with the glass tubing hole still covered, invert the flask and SUBMERGE it in the room temperature water bath. (sink)
10- Remove the finger from the glass tubing and allow the water to enter the flask.
11- When it appears that no more water is entering the flask, slowly raise the flask so that the water line of the sink is level with the water line in the flask and wait approx. 30 seconds.
12- Placing a finger again over the tip of the glass tubing remove the flask from the room temperature water bath and place the flask on the table
13- Carefully remove the rubber stopper and transfer the water into the graduated cylinder and record the volume
14- OVER THE SINK OR TOWEL completely fill the flask, until it overflows and then replace the rubber stopper (more water will spill out)
15- Remove the stopper carefully allowing any water in the glass tubing to enter the flask. Transfer the water from the flask into a graduated cylinder and record the maximumvolume of the flask (Volume 1)
16- Using data collected in steps 13 and 15, calculate the volume of air that was present after the room temperature bath. (Volume 2)
16- Repeat steps for remaining flasks (2 trials for each flask)
Data Table:
Table 1: Temperature and Volume
Flask Size / Vol. 1(mL) / Temp 1
(°C) / Vol. 2
(mL) / Temp 2
(°C) / Vol. of Water in flask (mL)
125 ml
125 ml
250 ml
250 ml
*** To calculate “Volume 2”, subtract “volume of water in flask” from “Volume 1”
To Submit:
1. Data tableand sample calculations (how you calculated V2) (5 marks).
2. Graphed data:
Use the average V1 and T1 as well as V2 and T2for each flask to create two lines on your graph. Extrapolate both lines to determine your average absolute zero (where both lines cross the x-axis). Your experimental value for absolute zero will be the average of the two x-intercepts. Identify the points on your graph, give your graph a title, label the axes and include units. Show how the x-intercept is calculated mathematically if you are drawing your graph by hand. Volume (dependent variable) goes on the y-axis, temperature (independent variable) goes on the x-axis. (10 marks)
3. Analysis (10 marks):
a) Comment on your result compared to the accepted value for absolute zero (is your value close, what can the error be attributed to?) (4marks)
b) Calculate the percent error of your value for absolute zero (2 marks)
c) Calculate what “Volume 2” should have been for each trial according to Charles’ law (4 separate calculations). (4 marks)
To prepare for lab:
-Review the concepts of Charles’ Law and Absolute zero
-Bring in one absorbent rag (ex: old towel) as the lab can get messy and you will be responsible for keeping your work station clean