This document summarizes an experiment on the ideal gas law. The experiment measured gas volume at different pressures and temperatures. Graphs of pressure vs volume and PV/T vs pressure showed exponential decay, consistent with ideal gas behavior. Mole calculations for the gas at 24C yielded values close to each other, further confirming the gas behaved ideally. The results demonstrate that the ideal gas law can accurately model real gases under certain conditions of low pressure and high volume.

1. PHYSICS ENGINEERING DEPARTMENT
FIZ341E - Statistical Physics and Thermodynamics
Laboratory
Name of Exp. : The Ideal Gas Law
Date of Exp. : 12.11.2014
BARIŞ ÇAKIR
090100235

2. Introduction
In real life there is no ideal gas; however ideal gas law and ideal gas states
are very useful to describe any gas. This states and law can be applied on nearly
ideal gasses which are in very low temperature and have very high volume. This
assumption does not let any interaction between gas molecules. Ideal gas
equation, derived from 3 different law from experiments on gasses. These are
Charles’ Law, Gay-Lussac Law and Boyle’s Law.
Charles’ Law: This law takes pressure as a constant and investigates relation
between volume and temperature, and the state to resemble the following;
( )
=
( )
Gay-Lussac Law: In this statement volume is kept constant, and the equation
becomes like the equation below;
( )
=
( )
Boyle’s Law: Boyle keeps temperature as constant and investigates relation
between pressure and the volume;
=
If these 3 equation mathematically combined, under the ideal gas conditions,
. = . .
Ideal gas law can be derived.
Experimental Procedure
Tools and devices: Gas law apparatus, mercury, mercury tray,
thermometer, thermostat.
First, thermometer is set to 24 o
C, later volumes calculated for 5 different
pressure value. This step repeated for 30 o
C, 40 o
C, 50 o
C, 58 o
C, 67o
C
temperatures.
For calculating these data, we use some king of manometer which acts
like open-ended manometer, so we added or substracted mercury levels from air
pressure.
With these calculated values, we draw the pressure against volume and
pressure times volume per temperature graphics and compared them with ideal
gas graphics.

3. Finally, for 20 o
C the number of moles of the gas in the reservoir
calculated.
Data Analysis
We calculated each volume by multiplying distance between mercury
probes and area of manometer’s tube.
( − ). =
Also we calculated pressure for adding distance to the air pressure;
+ ( − ) =
Already known constants are;
= 1.93 = 76
24°C 30°C 40°C
V (cm^3) P (cm-Hg) V (cm^3) P (cm-Hg) V (cm^3) P (cm-Hg)
25.36066 84.9 25.74784 85.2 26.52221 84.5
27.10299 80.7 26.9094 80.8 28.84533 81.1
28.65173 76 28.26455 76 29.03892 76
29.81329 71.2 29.4261 73.1 32.33 72.5
30.97485 66.4 31.36203 67.9 31.55563 68.1
50°C 60°C 70°C
V (cm^3) P (cm-Hg) V (cm^3) P (cm-Hg) V (cm^3) P (cm-Hg)
26.9094 85.7 28.07096 84.3 28.45814 86.5
28.45814 81.5 29.4261 80 29.81329 81.3
29.6197 76 30.39407 76 31.16844 76
30.58766 72.6 31.55563 72.2 33.29796 69.1
31.94281 68.4 32.52359 68.6 35.0403 64.9
Table1. Measurements for each temperature value

4. Graphic1. Pressure against volume graphic
24°C 30°C 40°C
PV/T P (cm-Hg) PV/T P (cm-Hg) PV/T P (cm-Hg)
7.249561 84.9 7.239987 85.2 7.16015 84.5
7.364348 80.7 7.17584 80.8 7.473981 81.1
7.331757 76 7.089458 76 7.050984 76
7.147159 71.2 7.099169 73.1 7.488577 72.5
6.925016 66.4 7.027993 67.9 6.865617 68.1
50°C 60°C 70°C
PV/T P (cm-Hg) PV/T P (cm-Hg) PV/T P (cm-Hg)
7.139738 85.7 7.127655 84.3 7.176761 86.5
7.180614 81.5 7.090628 80 7.066532 81.3
6.969341 76 6.957678 76 6.906127 76
6.875121 72.6 6.862398 72.2 6.708131 69.1
6.76436 68.4 6.720236 68.6 6.630073 64.9
Table 2. PV/T constant according to pressure
60
65
70
75
80
85
90
25 26 27 28 29 30 31 32
Pressure(cmHg)
Volume (cm^3)
24C 30C 40C 50C
60C 70C Expon. (24C) Expon. (30C)
Expon. (40C) Expon. (50C) Expon. (60C) Expon. (70C)

5. Graphic2. PV/T against pressure graphic
Finally, each moles calculated with the 5 data in the 24 o
C with the following
formula;
=
R is universal gas constant and it equals;
62.36367(11)×106
cm3.
mmHg.K−1.
mol−1
Our mole values for 24o
C are given in table 3.
mol (24°C)
n1 0.872390041
n2 0.886203138
n3 0.882281191
n4 0.860067283
n5 0.833335293
Table3. Moles for 24C
Conclusion
In ideal gas experiment we investigated ideal gas law on real gas, we can
check our results, with 2 different way.
One of them is graphic, we already know pressure against volume graphic
for ideal gas is exponential decreasing graphic, so if we check Graphic1 in the
data analysis part, we already got same kind of graphic for each temperature
value.
6
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
60 65 70 75 80 85 90
PV/T
Pressure cmHg
24C 30C 40C 50C
60C 70C Linear (24C) Linear (30C)
Linear (40C) Linear (50C) Linear (60C) Linear (70C)

6. Second one is mole numbers of each data in 24o
C, if we check Table3 for
n1,n2,n3,n4 and n5 we can easily observe these 5 value are very close,
considering that all n values belong to same gas, this result is expected.
As a result, ideal gas law works perfectly on real gases.
Resources
 http://en.wikipedia.org/wiki/Gas_constant
 http://en.wikipedia.org/wiki/Ideal_gas
 Thermodynamics LAB FÖY
Answers
1- Pressure is constant at this question so, if we use Charles’ Law at
introduction part T should equal to 137 K.
2- In this question we are going to use PV/T is constant for same gas so,
1.01 . 25
25
=
. 15
35
= 2.33