Mullen – N5 Physics Assignment
To investigate the effect on pressure when the volume of a
fixed mass of gas is decreased.
In a gas, intermolecular forces are weak which allows
particles to move around. As they move around, they may collide with each other
or the walls of their container. If the volume of the container is decreased,
the number of particles per unit area is increased. Hence, collisions occur
more frequently. If the temperature is increased, the particles move with more
kinetic energy which means collisions occur more often and due to collection
more kinetic energy, the particles collide with a greater force.
Pressure can be calculated using the equation:
Where P is the pressure in Pascals (Pa)
Where F is the force in Newtons (N)
Where A is the area in meters squared (m2)
Therefore, it can be determined that if area is decreased,
pressure will increase and if Force is increased, pressure will increase.
Lord Kelvin created a new temperature scale. At -273oC
particles have no kinetic energy and so do not move or strike against the walls
of the container. Hence, to convert from degrees Celsius to degrees Kelvin,
simply subtract 273. It is for this reason that when measuring the temperature
of a gas, it would make sense to use the Kelvin scale.
The Gay-Lussac Law states that a gas which is at a constant
volume has a pressure which is directly proportional to the Kelvin scale. This
law is responsible for the equation:
Where P is pressure in Pascals (Pa)
Where T is temperature (Degrees Kelvin)
Where C is a constant
This means that as pressure increase, so does the temperature.
A fixed mass of gas was trapped in a tube with oil. Going
along the tube was scales indicating the volume of air inside. The volume of
air was altered by pumping oil into the tube. The tube was connected to a
bourdon-gauge. We measured the volume of air inside the tube and then the
pressure in kPa.
Air Volume (cm3)
Taken from: https://www.google.co.uk/search?q=pressure+vs+1/volume=strict=lnms=isch=X=0ahUKEwj5vKmfk9zYAhUBB8AKHUK4A28Q_AUICigB=1366=637#imgrc=PSUZhub0YmmhPM: on
This graph shows that as volume increases, pressure decreases.
The line graph is a straight line which goes through the origin, hence
indicating that pressure and volume are inversely proportional.
My graph also shows that pressure and volume are inversely
proportional because my graph adopts the same straight line through the origin
when plotting Pressure against 1/Volume.
Therefore, I am able to conclude that pressure and volume are
inversely proportional. Subsequently, if the volume of a gas is decreased, the
pressure will increase.
To increase the accuracy of my results, I repeated the
experiment three times and then calculated the average. This means that any
inaccurate results were more likely to be cancelled out by more accurate