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Video-Charles Law ExperimentÃ¯Â¼Å¡

Charles Law- data sheet

on the fileÃ£â‚¬â€š

Data Table:
Trial 1
Trial 2
Temperature of boiling water (T1)
100. Ã‚Â°C
100. Ã‚Â°C
Temperature of air after cooling on the water bath
(T2)
23.0 Ã‚Â°C
23.0 Ã‚Â°C
Initial volume of air in the flask at the temperature
of boiling water (V1)
138 ml
255 mL
Volume of water drawn into the flask (V H20 )
26.0 mL
47.0 mL
Volume of moist air (V2 wet) drawn into the flask
when cooling. V2 wet = V1-V H2O
Volume of air collected at the cool temperature
after the vapor pressure correction in Equation 2.
(V2 measured)
Volume of air collected at the cool temperature
calculated using Charles’ Law (V2 calculated)
Atmospheric pressure in mmHg (P total)
760. mmHg
760. mmHg
Water vapor pressure (in mmHg) at temperature T2
(P water) (from Table 1)
Percent error between V2 measured and V2
calculated
Table I. Vapor Pressure of Water as a Function of Temperature
Temperature (0)
Vapor Pressure (mm) Temperature (C) Vapor Pressure (mm)
20
21
10
11
12
13
14
15
16
17
18
19
9.2
9.8
10.5
11.2
12.0
12.8
13.6
14.5
15.5
16.5
17.5
18.6
19.8
21.1
22.4
23.8
25.2
26.7
28.3
29
30
30.0
31.8
Calculations:
a. The air collected in the flask at the lower temperature also contains water vapor. So we refer
to this volume as Vz wet. We can calculate V2 wet by subtracting the volume of water (V H20)
drawn into the flask from the initial volume of air in the flask V1.
b. In order for us to calculate the volume of air collected at the cool temperature (V2 measured)
, we have to use a vapor pressure correction. This correction is done using the Daltons Law of
Partial Pressures. In Equation 2, we subtract the vapor pressure of water in the flask at the
cooler temperature to calculate the experimental value of V2 (V2 measured).
P total-P water
V2 measured=V2 wet x
Equation 2
P total
C. Using Charles’ Law calculate the theoretical value for V2 (V2 calculated) by substituting values
for V1, T1 and T2 in equation 1. Show your work below.
d. Calculate the Percent error in between your experimental and theoretical value for V2:
|V2 measured-V2 calculated
% error=
x 100%
V2 calculated
Show your work for calculating % error:
Name:
Discussion questions:
1. Why do we need to clamp the rubber tube when we are transferring the flask from the boiling
water to the cool water? Explain how this will affect your results.
2. If a balloon holds 3.7 L of gas at 25 Ã‚Â°C, what will be the volume of the balloon at 46 Ã‚Â°C?
Assuming constant pressure. Show your work.
3. Discuss two sources of error in this experiment that might account for a high percentage error
between V2 measured and V2 calculated.