Mr. Kostecki "The Ideal Gas Law Lab" Section 3

The Ideal Gas Law
Experimenters: Eric Tuvell, Molly Lorenz

Main Purpose: Using the Ideal Gas Law, we should be able to understand the different relationships between pressure, temperature, volume, and how they work ideally at a molecular level.

3) T&V Materials Used:
Gas Law Apparatus Syringe
Air Chamber and Tubing
Short Pieces of Tygon Tubing
Computer Based Laboratory System
2 Large Insulated Containers
Hot Water
Ice
Pressure Sensor
Temperature Sensor
RealTime Physics Heat and Thermodynamics experiment configuration files

3) T&V Predictions:
Prediction 1-3: A low-friction syringe containing air is moved from a water bath at one temperature to one at a higher temperature. (The syringe is left long enough so that the air is in thermal equilibrium with the water baths.) How does the volume of the air change? What do you think will be the mathematical relationship between V and T with the pressure held constant?
We thought that the volume will increase, and that the relationship between volume and temperature will be linear.

3) T&V Experimental Procedure:
After connecting the flask to the pressure probe and to the syringe, we opened Measuring V and T (L05A2-3) on the computer, as both the temperature and pressure sensors were already connected to the computer interface. While some dimensions of the tubing were already given to us, others were not, so measuring with a piece of string, we arrived at our estimated volume of tubing at 8.5 cm3. Setting up Table 1.3 (see attached) with our volume of tubing, and the volume of the sensor being 0 cm3. The flask was submerged in the cup of warm water (approx. 343 K) when the graphing simultaneously began. The sensor was disconnected from the syringe after the pressure and temperature had stopped fluctuating. Then, the piston on the syringe was pulled out to 20 mL and the valve was closed off. After the pressure and temperature had once again, stopped changing, we kept the data point and entered the total volume. After that, every time ice was added to the cup of hot water, the syringe was adjusted so that is remained isobaric, and we kept data points and entered in the new total volume. We repeated that until we had 5 data points down to 3 cm3 as the volume of air in the syringe. Lastly, we used the fit routine to find the relationship between V and T and printed the graph.

3) T&V Analysis:
Question 1-5: What is the relationship between V and T? Is it proportional, linear, inversely proportional, or something else? Did this agree with your prediction?
The relationship between volume and temperature was proportional linear and it did agree with our prediction.
Question 1-6: Write down the relationship between the initial pressure and volume (ViTi) and the final pressure and volume (VfTf) for an isothermal process.
ViTi= 45.5 cm3, VfTf= 16.5 cm3 The initial is larger then the final.

Question 1-7: Are the relationships you found in the past three activities consistent with the ideal gas law? Explain based on your investigations of Boyle’s law, Gay-Lussac’s Law, and Charles’ Law.
The last three activities were consistent with the ideal gas law, PV=nRT. Boyle’s Law, Gay-Lussac’s Law, and Charles’ Law all coincide with one another for the Ideal Gas Law. If one of these laws were false, then they all would, by extension, be false as well.

Ideal Gas Law: PV=nRT
Boyle’s Law: P1V1=P2V2
Gay-Lussac’s Law: P1T2=P2T1
Charles’ Law: V1T2=V2T1

3) T&V Conclusion:
The conclusion was that Charles’ Law was true, stating that V1T2=V2T1. Additionally, the other gas laws were also proved correct.