Boyles Law Pre Lab
Miranda Holson
3/27/13
Chemistry – A
Mrs. Parkhurst

I Background Boyle’s Law states that the volume of a fixed mass of gas varies inversely with pressure at a constant temperature.

II Purpose The purpose of this experiment was to show that the pressure on the air in the syringe was varied because of Boyle’s law, which states that the volume of a fixed amount of dry gas is inversely proportional to the pressure, while the temperature is held constant.

III Procedure The first step was to adjust the head on a syringe so that there was 35-40mL of air trapped in the syringe, and hold the air by capping the syringe with an airtight plastic tip. Next was to read the volume of air in the syringe to make it as close to tolerance as the accuracy of the syringe will allow. Next was to record that volume as the initial volume for zero weights in your data table. Then was to balance the first weight on the piston. Then by measuring the chemistry books as a constant mass. Then twisted the piston gently overcoming any frictional forces until the piston had come to a rest. Next was to record the volume of gas inside the syringe, and then repeat the procedure until there were an adequate number of books balanced on the piston. After reaching about four books then was to remove the books and allow the system to return to zero pressure. Next was to repeat each step a second time. It was important to know that to get the volume back to the original reading it might take twisting the piston several times. Last was to repeat the fourth step, giving three separate sets of data for each of the five pressure measurements.

IV Conclusion w/ Calculations and Analysis

# Books “pressure” | Trial 1 Volume | Trial 2 Volume | Trial 3 Volume | Average Volume | 0 | 40 | 40 | 40 | 40 | 1 | 29 | 39 | 31 | 33 | 2 | 24 | 26 | 24 | 24.6 | 3 | 19 | 19 | 20 | 19.3 | 4 | 16 | 15 | 16 | 15.6 | 5 | 14 | 14 | 14 | 14 |

Calculated Averages:

40 + 40 + 40 / 3 = 40
29 + 39 + 31/ 3 = 33
24 + 26 + 24 /3 = 24.6
19 + 19 + 20 /3 = 19.3
16 + 15 +16 /3 = 15.6 14+ 14 +14 /3 = 14

This experiment proves Boyle’s Law by showing that when pressure increases volume decreases. The more books placed on top of the syringe minimize the volume of the air inside the syringe. This is shown very clearly in graph one. Gases are compressible because their molecules are more spread out and when the pressure increases they become more compact and the