*Assuming that the diameter of the tube is constant, then the volume of the gas directly proportional to the height of gas column.
Evaluation:
The experiment shows the relationship between the pressure of the gas and its volume at constant temperature. According to Boyle’s Law, in a constant temperature, the volume of gas is inversely proportional to the applied pressure put on the gas.
V ∝ 1/P
V = k/P (k is a constant)
VP = k
Theoretically, when graph PV against V (volume) is plotted we should get constant graph or one straight line stretches through the y- axis. Unfortunately, this kind of graph fails to be obtained due to some limitations.
Experiment 2 - Charles’s Law.
Hypothesis:
The volume of gas is directly proportional to its temperature.
Variables:
- Independent: The temperature of the environment
- Dependent :Volume of the gas
- Constant: Pressure of the gas.
Result:
*Assuming that the diameter of the tube is constant, then the volume of the gas directly proportional to the height of gas column.
Evaluation:
The experiment shows the relationship between the temperature of the gas and its volume at constant pressure. According to Charles’s Law, at a constant pressure, the volume of gas is inversely proportional to the absolute temperature of the gas.
V ∝T
V = kT (k is a constant)
V/T = k
Theoretically, when graph Volume (V) against Absolute Temperature (K) is plotted we should get a liner graph with k (the constant) as a gradient of the graph. Unfortunately, this kind of graph fails to be obtained due to some limitations.
Experiment 3 - Ideal Gas Law
Results:
Mass of the conical flask + foil + rubber band: 67.8405 ± 0.0001g
Mass of the conical flask + foil + rubber band + condensate: 67.9441 ± 0.0001g
Mass of condensate: 0.1036 ± 0.0001g
Temperature of the boiling water: 97.0 ± 0.5 ºC
Barometer reading:
Volume of the conical flask (represents the volume of the condensate): 155 ± 0.5 ml
Based on Ideal gas equation:
PV = nRT
P= Pressure applied
V= Volume of the gas
T= Absolute Temperature
n = number of mol
R= Gas constant
We know that, mass /relative molecular mass = number of mol
m/M = n
Hence, PV = nRT
PV = m RT
M
M= m RT
PV
In this case,
R: 8.134JK-1mol-1
P: 733mm Hg X 101.325 kPa
760mm Hg
=97.7253 kPa
V: 155.0 cm3
1000
=0.155 dm3
T: 73.30 ºC + 273.15
=376.42 K
Relative molecular mass of unknown compound can be determined using this formula,
M= m RT
PV
=(0.1036 g)( 8.134JK-1mol-1)( 376.42 K)
(97.7253 kPa)( 0.155 dm3)
=20.9 gram mol-1
Limitations and recommendations:
Conclusion: The gas law is mathematically related to the temperature (T), pressure (P) and volume (V). The relationships are stated by Boyle’s Law, Charles Law and Ideal Gas Law.
