Pressure, Volume, Temperature Relationships

Lab Day 3: March 2, 2015 Relationships between Pressure, Volume, and Temperature

Pressure:
Can Experiment:

Lipton Iced Tea Can predictions

In this experiment, we predicted that the iced tea can will rapidly implode because the gas wants to escape the can due to the pressure built up inside from the heat.

Heating the bottom of Lipton iced tea can with a torch
 (steam is present)

The iced tea can did in fact implode as predicted where we see that the can had air inside from heating and it imploded instantly. 

Only hot air experiment

After putting it in water

Predictions of just hot air in the can

On the other hand, with only hot air, the can sucked in water as seen in the picture.

Analysis of units in pressure

Project 1:Pressure Vs. Volume Relationship

In this experiment an syringe was setup where we compressed air in small increments to change the volume and pressure.

Quadratic fit graph logger pro data

The quadratic fit is seen a bit off from the curve therefore, the second linear fit is a better fit for the relationship.

Fit parameters on logger pro results

The shape of this fit in the experiment we performed showed that it has a relationship that is inversely proportional. Therefore we analyzed the graph and had a linear and quadratic fit where we chose the linear fit to be a better fit for pressure vs volume relationship. The graph is a curved shape where the volume decreases as the pressure increases. In the beginning, there is a sharp reduction in the volume as the pressure increases. The decrease in volume then becomes more gradual and the volume appears to level off as the pressure increases further. It is some sort of hyperbolic curve where it is obtained through the inverse relationship between the two variables where y=A/x.

Simple Representation of inverse relationship

calculations of units of pressure

The slope from the fit was used to find the units of pressure above.

Project 2: Pressure Vs. Temperature Relationship

    

Charles law relationship of Pressure and Volume predictions

Apparatus of Pressure vs temp.

The apparatus used was to measure pressure vs. temperature where the flask was the test volume of gas and by immersing the flask in a container of heated water, we added ice chips to measure the relationship. 

Logger pro graphical representation of pressure vs temp relationship

Simple representation of P vs T (Charles Law concept)

In fact the graph shows results of a straight line where it is a proportional relationship in which the pressure remains constant even if the volume of air in the system changes because the greater pressure on the inside of the container walls will push the gas outward which increases the volume. As a result, the gas molecules will have more space to go, therefore lowering the number of collisions and decreasing the pressure to its constant value.

Project 3: Volume Vs. Temperature Relationship

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In this experiment, the beaker is filled with water where we added ice to the reduce the volume of the trapped air, where we pulled the plunger out at the 9 cc mark. 

Volume vs Temperature Relationship 

The results show that the volume is directly proportional to the temperature of gas in which doubling the temperature will also double its volume and the slope is constant. Charles law is also represented in this case.
Boltzmann/ univeral gas constant

Relationship of Boltzmann constant and universal gas constant (Avogradro's number relationship)

Diving Bell Problem:

Diving Bells Calculations Part A: Pressure total

Diving Bells Calculations Part B: Height

This problem was an great example of diving bells and the idea of pV=nRT where we have changes in height and a relationship between pressure, volume and temperature in one problem that applies the gas relationships we experimented and analyzed.

Marshmallow Experiment:

Marshmallow predictions (Pressure and Volume)

Marshmallow apparatus where pressure can be sucked out and in for the vacuum.

Video on marshmallow experiment

In this part when the pressure decreases, the volume increases where our marshmallow expanded as we sucked out the pressure from inside. (unfortunately some marshmallow pictures were deleted :(( ) but it got bigger from the observations. On the other hand when the pressure increased, the volume decreased causing the marshmallow to get smaller. When it went back to the initial state, the marshmallow became shriveled because the air escaped.

Balloon: calculations of maximum mass of helium in the balloon

We were able to identify three different relationships between pressure, volume, and temperature in different experiments. The first experiment observed that the pressure and volume had an inverse proportional relationship that shows that the volume increases as the pressure decreases. Another experiment analyzed the proportional fit of a straight line where pressure remains constant even when the volume changes in correlation to the temperature. The last experiment showed that volume is also directly proportional to temperature where the slope is constant. These ideas based on Boyle's and Charles law helped us derive the equation of the ideal gas law where the three experiments were all in effect using Boltzmann's constant and the universal gas constant. The results seen in the can and marshmallow experiment, showed that pressure, volume, and temperature can be used to determine the interactions of gases.