Experiment Number 7

 

Experimental Verification of the Gas Laws

 

 

California Content Standards

 

This experiment will ask students to develop a series of mathematical relationships based upon the behavior of gases under different conditions (SCSCPS, p 37).

 

 

 

 

Introduction

 

Purpose:  The purpose of this experiment is to measure changes in the pressure of gas when volume and temperature are changed and then use this information to develop a mathematical relationship between a change in volume and pressure and between a change in temperature and pressure..

 

Hypothesis:  You will need to predict what the relationship what effect a change in volume or temperature will have on the pressure of a gas.

 

Background:  .

 

Include a paragraph or two on the historical development of the gas laws and their relationship to modern chemistry.

 

 

 

 

Materials & Methods

 

Materials:       Air

 

Equipment:   

 

Pressure guage (manometer)                     125 mL flask or 25 x 200 mm

Thermometer                                     600 mL beaker

One hole rubber stopper                              Rubber/plastic tubing tubing

20 mL syringe                                                Hot plate/ stirrer

Stirring bar

 

Safety:

 

Hot plates remain hot after being turned off.  Also, be careful that tubing and other plastic ware does not touch hot plate. 

Pre-Lab Procedure

 

1.         Examine the lab procedure and prepare a flow chart for how you expect to conduct the exercise.

 

2.         Familiarize yourself with the gas laws.

 

Procedure:

 

1.         In the first experiment use the manometer (pressure sensing device) and a 20 mL syringe to examine the relationship between volume and pressure.  Obtain at least five data points for your graph.  Use this information to verify the mathematical relationship between volume and pressure.

 

2.         In the second experiment, us the flask, the rubber stopper, glass tubing and rubber tubing to set up an experiment to investigate the relationship between temperature and pressure.  Adjust the temperature of the flask using a water bath.  Use at least 5 data points to develop the relationship.  Use the information to verify the mathematical relationship between temperature and pressure.

 

 

 

 

Results & Conclusion

 

Results:

 

Plot each of your graphs in Excel or some other spread sheet program.

 

 

Discussion/Conclusions:

 

In your discussion/conclusion section of your report discuss specifically how the results relate to your hypothesis.  Compare the two experiments and discuss how they differ and why.  Be sure to discuss potential sources of error in your experiment and how the experiment might be improved or modified to obtain better results.

 

 

 

 

Questions

 

1.         Is the effect of temperature on the flask instantaneous?  Explain.

 

2.         If the flask were at less than atmospheric pressure and heated, what changes in the pressure would take place?

 

3.         What useful invention to Robert Boyle develop from his work?

 

4.         What do you suppose would happen to a gas eventually if you kept increasing the pressure?

 

5.         On the temperature versus pressure graph, what should be the intersection of the graph with the x-axis?