Gas Law Lab Report

The task of this lab is to create and analyze hypotheses of the different relationships between the properties of gasses. These properties include temperature, pressure and volume. The ideal gas law is the source for many of these hypotheses and are tested through the various known laws of gasses. Such laws include Lusaacs Law, Charles Law and Boyles Law. The data, gathered from the results of the experiments mentioned above, was then graphed to show the relationship between the properties that gasses inhibit. The data provided was also utilized to derive a proportionality constant, k. Pressure rises when temperature rises, pressure rises when volume falls and volume rises when temperature rises. All of these outcomes were observed during the

conduction of the three experiments.
Three experiments were conducted to find the relationship between the known properties of gas. That was the purpose of the lab. The ideal gas law states that a property of gas can be found if three others are known. This equation is known as:
pressure (P) * volume (V) = moles (n) * gas constant (R) * temperature (T) or PV = nRT
R is the known gas constant or the volume of any known gas at standard pressure and temperature (STP). R always stays the same in every ideal gas law equation. The three trials that have been mentioned above were carried out by holding two of the properties constant and analyzing the correlation between the other two. The trials were based around the known gas laws that were also mentioned above.
The first trial conducted dealt with Boyle’s Law.

Boyle’s Law includes holding the temperature constant while analyzing the correlation between volume and pressure. An electronic tool was used in this trial called a LabQuest. As the volume of water is manually reduced, the LabQuest measures the pressure of the closed system while temperature is held constant. While analyzing the data and reading the measurements it was concluded that when volume is decreased, pressure will increase and as volume is increased, pressure will decrease. This was concluded because all the other properties in the ideal gas law were constant.

The second trial conducted dealt with Gay-Lusaac’s Law. Gay-Lusaac’s Law includes holding the volume constant while looking at the relationship between pressure and temperature. A flask was immersed into an ice bath and the pressure was recorded. The temperature of this ice bath was then raised and the pressure was measured each time the temperatures of the ice bath was raised. Pressure and temperature are inversely proportional, meaning as temperature goes up and the pressure does also. The same happens when the temperature is decreased. When temperature is decreased the pressure also

decreases.
The third trial dealt with Charle’s Law. Charle’s Law includes holding the pressure constant and inspecting the connection between volume and temperature. This was also done by creating ice baths of increasing temperature and measuring the volume at a constant pressure with each increase in temperature. Volume and temperature are also inversely proportional. So as temperature rises, pressure does also and as temperature decreases, pressure decreases too.
Trial One
Boyle’s Law
As described above, Boyle’s law looks into the correlation between pressure and volume while temperature is held constant. The trial was set up by attaching a syringe to a ring stand and then attaching a pressure sensor, measured through the LabQuest, to the bottom of the syringe. After everything was set up, the starting volume and pressure were measure and documented in the lab manual. A clamp handle was then used to manually decrease the volume by 5 mL five separate times. After each 5 mL interval the change in pressure was documented for each of the five separate times. A program called LoggerPro was then used to graph the results from the completed trial.
Trial Two
Gay-Lusaac’s Law
In Gay-Lusaac’s law the correspondence between pressure and temperature are evaluated at a constant volume.

A pressure sensor was sealed inside a closed Erlenmeyer flask. That flask was then immersed into an ice bath where a temperature sensor is also immersed. The ice bath was set to 0 degrees Celsius or 273 Kelvin. The starting measurements were again observed and documented in the lab manual. Hot water was added to the bath until the bath rose 10 Kelvin in temperature. The pressure was recorded when it stabilized. This processes was repeated three more times until the four measurements spanned a temperature range of 40-50 K. LoggerPro was used to graph the data

points.
Trial Three
Charle’s Law
Charle’s law looks at the correlation of volume and temperature while pressure is held constant. The pressure and temperature sensors that stem from the LabQuest were set up to measure the pressure and temperature while another apparatus was set up the measure the volume. This system was completely closed and immersed into an ice bath. The initial pressure was recorded. The ice bath was then raised 10 K. After the temperature of the ice bath was raised, the apparatus that was set up to record the volume was used to increase the volume until the pressure reached a number extremely close to the first observed pressure. The temperature and volume were then documented into the lab manual. This process was then repeated three more times to come to a total of four varied ice bath temperatures. After the four trials were conducted, the outright volume had to be determined by adding up the volume of the bottle, syringe and tubing from the apparatus. The volume of the bottle was found by filling it with water and then measuring it in a graduated cylinder. The volume of the tubing was calculated by the LabQuest when the pressure was determined and the volume of the syringe was recorded in the trial. Once again, the data found was graphed using logger pro.

Proportionality Constant: k=P/(V)n
K Value Mean: Xm=(k1+k2+k3+kn)/n
Standard Deviation of K values: Sx=[(d12+d22+d32+dn2)/(n-1)]1/2 and di = | xm – xi |
Standard Deviation of the Mean: Sm = Sx / √n
Confidence Interval at 95%: CI = Xm ± t*Sm
Results

All graphs created with LoggerPro had to be linear with a correlation of .98 or higher so the n value for the first graph had to be changed to -1. The fact that the n value had to be changed explains why pressure and volume are directly proportional and one increases when the other decreases or decreases when the other increases. The accuracy of this graph is defined by the correlation, which is .9996. The calculated mean of the k values for the first trial is 31.5. Using that number, the standard deviation was found and that was 14.35. After the standard deviation was found, the standard deviation of the mean was found and that number is 5.86. Thus the confidence interval at 95% was found to be 31.5 + or – 15.0602.

This graph was already linear when the data points were plugged in so so n values had to be changed. That explains why temperature and pressure are inversely proportional, meaning as one goes up, so does the other. The correlation of this graph is .9995, which defines the accuracy. The mean of the confidence intervals was found to be .0036. Using that mean value the standard deviation was calculated and that number was 3.8 x 10^-9. Next, the standard deviation of the mean was found and that number was 1.9 x 10^-9. Finally, the confidence interval at 95% was found to be .0036( + or – )6.024 x 10^-9.

The third and final graph created using LoggerPro was also already linear, so no n values had to be changed. This describes why volume and temperature are inversely proportional meaning as one goes up the other does too. As one goes down, the other does too. The correlation of this graph shows the accuracy and that is .9979. The mean of the k values was found to be 2.5775 x 10^-4. Using that number the standard deviation can be calculated. The standard deviation was found to be 8.660 x 10^-4 and the standard deviation of the mean was found to be 4.33 x 10^-4. Finally the confidence interval at 95% was calculated to be 2.5775