Analysis Constant Temperature
TD-8596A
5
012-08420B
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 tempera-
ture (T
1
), in Table 2.
2.
Record the initial volume (V
1
), including your calculated value of V
o
.(V
1
is 40 cc)
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.
4.
Record the volume (V
2
), (including V
o
) of the fully compressed plunger.
5.
The Ideal Gas Law states that the quantity.
Use your values to calculate the ratio
Use your values to calculate the ratio
6.
Compare these two ratios. Are they about the same? Calculate the percent difference between them.
Table 2: Varying Temperature
Volume (cc)
Pressure (kPa)
Temperature (K)
1
2
V
1
V
0
+
V
2
V
0
+
-------------------
P
2
P
1
------ (2)
=
PV
T
--------
Constant.
=
P
1
V
1
T
1
-------------
P
2
V
2
T
2
-------------
Percent Difference
Value #2 - Value #1
Value #1
---------------------------------------------------- x 100 (%)
=
