Lab 2 Wednesday 26Feb2014

Linear thermal expansion

Rods is clamped up and stream is sent through one end with a rotary sensor to measure the angle it moved when the rod expands. This will allow us to determine the linear heat expansion constant, α.

The graph show the change in the angle which is 17 degrees and temp change of the rod which is 76^oC.

This picture represents the linear heat expansion constant calculated from the initial length , change in temperature,  and change in angle due to the rods expansion. Therefore, the linear heat expansion constant α=2.93x10^-5 C^-1.

The uncertainty was calculated for the linear heat expansion constant thus, α=2.93x10^-5 ± 3.904x10^-6 C^-1. To determine the material of the rod used in the experiment we can compare the linear heat expansion constant. Given the uncertainty we can assert the rod is made of Aluminum since it has a linear heat expansion constant of α=2.4x10^-5 C^-1 which is very close to our value with the uncertainty included.

Latent Heat of Vaporization

Immersion heater with a power of 297.6 W was used a known mass of water while the temperature probe was used to measure the change in temperature in logger pro.

This graph was taken during the experiment and gave us the time required to create water vapor this is then multiplied by the power of the immersion heater to get the heat required to create water vapor. The graph levels out at 100 ^oC because the water is being vaporized.

The latent heat of fusion was determined by finding the change in mass after the water vaporized then using the relationship that from the picture above.  The latent heat of vaporization was determined to be 2409140J/kg.

The class gathered their data to compare results by taking the standard deviation of all the data. We added our data to the list later because we ran into issue with the logger pro. The standard deviation is the square root of the summation of each value minus the average value squared and divided by the total number of data points minus one. Our standard deviation is with in the expected range and is a good indication that the class results were accurate with respect mean. Therefore, the latent heat of vaporization can be represented as 2409140 ± 836164.998 J/kg.

Determining the Ideal Gas Law

P vs V (Boyle's Law):

A empty syringe was attached to pressure sensor and connected to logger pro in order to determine the relationship between pressure and volume.

We expected the graph of Pressure verses Volume to appear non linear as show in the picture above at the top. Pressure is inversely proportional to the volume, which can be seen when you manipulate the ideal gas law.

This graph calculated the relationship in the change in Pressure verses Volume; pressure is inversely proportional to volume. Which validated our prediction that they have a non-linear relationship which is verified by this graph Press=A/V. The value of A is based on the graph is 3288±40.22. The units of A are in Joules as proved in the previous picture. A is a form of energy because it’s a product of moles * R * temperature which gives us Joules but it is a constant product. A is the translational kinetic energy of moles of air molecules.  

P vs T for Gas (Charles Lawll)

The flask contains 150cc of gas or air and is in water with a temperature of 70 ^oC. Chips of crush ice were added to the cup with the flask. Temperature probes and a pressure sensor were used to measure the change in pressure as a function of temperature.

We expected the graph to change linearly since the ideal gas law tells us that Pressure is directly proportional to temperature.

This picture represent the graph of pressure verses temperature of the flask recorded during the experiment an it matches our predictions.