Varying temperature – PASCO TD-8596A Ideal Gas Law Apparatus User Manual
Page 6
Ideal Gas Law Apparatus
Model No. TD-8596A
4
®
3. For constant temperature, the Ideal Gas Law reduces to P
1
V
1
= P
2
V
2
, or
4. Take the ratio of the final pressure over the initial pressure P
2
/ P
1
. Take the ratio of the initial
volume over the final volume V
1
/ V
2
. Are they equal? Why not? There is actually a small
consistent error in the volume that you can account for. The calibration on the syringe does
not include the volume of air in the tubing. If we call this unknown, additional volume V
o
, the
equation (1) above can be more correctly written as
Using your measured values of V
1
, V
2
, .P
1
and P
2
, algebraically solve for and calculate the
volume V
o
.
Varying Temperature
1. Highlight an area on the temperature graph at the beginning of the run before you compressed
the air, as you did before. It does not matter if it is the same pressure point or not. Record both
the initial pressure (P
1
) and initial temperature (T
1
), in Table 2.
2. Record the initial volume (V
1
), including your calculated value of V
o
.
3. Highlight the area on the temperature graph where it peaks. Pick the place where the
temperature has peaked, not the pressure. It takes the temperature sensor about 1/2 second to
respond. Record the peak temperature (T
2
) and the corresponding pressure (P
2
) for that time
in Table 2. You want two values that occurred at the same time.
Table 1: Constant Temperature
Volume (cc)
Pressure (kPa)
1
40.0
2
V
1
V
2
------
P
2
P
1
----- (1)
=
V
1
V
0
+
V
2
V
0
+
--------------------
P
2
P
1
----- (2)
=
Note: V
1
40 cc