Download Charles`s Law Lab

Charles’s Law Lab
Name_______________________Hr_____
PRELAB QUESTIONS:
1. a) What is the barometric pressure in the room today, measured in mmHg? __________
b) Do you expect the barometric pressure to change during class today? _______
2. What happens to the motion of gas molecules when a gas is heated? _____________________
3. When molecules of a gas move faster inside a flexible container (such as a syringe) how does the
pressure of the confined gas change? __________________________________________
4. If a gas in a syringe is heated, how will the volume change?____________________________
5. If a gas in a syringe is cooled, how will the volume change?____________________________
PROCEDURE:
1. Obtain a syringe, remove the stopper at the end and adjust the volume to be about 20.0 cm3.
Replace the stopper for the duration of the lab in order to keep the number of air molecules
constant.
2. Gently pull up on the syringe and let it settle at equilibrium. Record the “pull up” volume of the
syringe in the data table below. Then, gently push down on the syringe and record the “push
down” volume. Finally, measure the temperature of the room and record below.
3. Fill a beaker with cold water and ice. Use a test tube clamp to position the syringe such that the
trapped air remains submerged for about 2 minutes. Determine both the pull up and push down
volumes. Measure the temperature of the ice water. Record all data below.
4. Boil water in a beaker on a hot plate. Immerse the syringe in the boiling water completely
covering the gas for about 2 minutes. Determine both volumes and measure the temperature of
the water as described above.
5. Plot the average volume versus temperature on both the graphs provided.
o Consider which variable is independent and which is dependent
o On the first graph, use a temperature scale of 0oC to 100oC
o On the second graph, use a temperature scale of -300oc to 100oC
o On the both graphs, use a volume scale that starts at 0.0 cm3
o Choose increments for volume and temperature that spreads the data out over the graph
o Label both axes with axis titles and units.
o Include one title for both graphs which best describes the data.
DATA:
Temperature
(oC)
Pull up
volume
(cm3)
Push down
volume
( cm3)
Average
volume
(cm3)
ANALYSIS:
1. a) Draw the best fit straight line through your points on each graph.
b) On the second graph, extrapolate (extend) the line to the x-axis, using a dashed line.
c) According to your data, at what temperature would the volume of the gas equal zero? _______
2. Describe the relationship between temperature and volume of a gas. Is this a direct or an inverse
relationship?
3. Explain the movement of gas molecules when the temperature is increased. How does the
kinetic energy of the molecules change?
4. Explain the actions of gas molecules when the temperature is decreased. How does the
kinetic energy of the molecules change?
5. Explain Charles’s Law, in your own words. Include all 4 variables of a gas in your explanation.
6. Draw a molecular view of molecules of air in a closed balloon in hot water and cold water,
holding pressure and number of moles of the gas constant. Use arrows to indicate changes in
molecular motion.
7. Describe one thing you learned in this lab.