pressure temperature phet

8/9/2019 Pressure Temperature PhET

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Lab: Pressure -TemperatureRelationship in Gases

Gases are made up of molecules that are in constant motion and exert pressure when they collidewith the walls of their container. The velocity and the number of collisions of these molecules isaffected when the temperature of the gas increases or decreases. In this experiment, you will study

the relationship between the temperature of a gas sample and the pressure it exerts. Using a onlinesimulation (screen shown inFigure 1) from the University of olorado!PHET Simulation - GasPropertiesThe volume of the gas sample and the number of molecules it contains will be "eptconstant. #ressure and temperature data pairs will be collected during the experiment and thenanaly$ed. %rom the data and graph, you will determine what "ind of mathematical relationshipexists between the pressure and absolute temperature of a confined gas. &ou will also do theextension exercise and use your data to find a value for absolute $ero on the elsius temperaturescale.

OBJECTIVES

In this experiment, you will

'tudy the relationship between the temperature of a gas sample and the pressure it exerts. etermine from the data and graph, the mathematical relationship between the pressure and

absolute temperature of a confined gas. %ind a value for absolute $ero on the elsius temperature scale.

Figure 1

Chemistry with Computers www.vernier.com Modified by Dr. Duane A. Dolejsi 07/22/09
http://phet.colorado.edu/en/simulation/gas-propertieshttp://phet.colorado.edu/en/simulation/gas-propertieshttp://phet.colorado.edu/en/simulation/gas-propertieshttp://phet.colorado.edu/en/simulation/gas-propertieshttp://phet.colorado.edu/en/simulation/gas-properties


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MATERIALS

computer

Logger Pro

PhET Simulation Gas Properties

PROCEDURE

. 'tart up your browser and go toPHET Simulation - Gas Properties.lic" on the *+unow- button and after the simulation starts, select olume for the onstant #arameter.

/. 0e will generate data for both a heavy species and light species of gas molecules. 'elect*heavy species- to start with.

1. #ump approximately atm of pressure into the container.

2. +ecord the Temperature in 3elvin (3) and #ressure in 4tmospheres (4tm) in the data table.alculate the elcius (o) Temperature by subtracting /51 from the 3elvin Temperature.

6. 4dd heat to the container, raising the Temperature by about 77 3. +ecord the newtemperatures and pressure.

8. +epeat the process until you have a total of 6 data values.

5. +eset the simulation and select *light species-. +epeat steps 1 9 8.

Heavy Species Light Species

T (o) T (3) # (4tm) T (o) T (3) # (4tm)

:. 'tartLogger Proand open the data file *Pressure_vs_Temperature-. This file may bedownloaded and extracted from!http!;;www1.northern.edu;doleT.$ip

?. >nter the @eavy 'pecies 3elvin Temperatures and #ressures in ata 'et . >nter the Aight'pecies 3elvin Temperatures and #ressures in ata 'et /.

7. ecide if your graph of pressure vs.temperature (3) represents a direct or inverserelationship (do this for both data sets)!

a. lic" the urve %it button, .

b. hoose your mathematical relationship from the list at the lower left. If you thin" the

relationship is a direct proportion (or direct), use #roportional. If you thin" the relationshiprepresents a power, use #ower. lic" .

B
http://phet.colorado.edu/en/simulation/gas-propertieshttp://www3.northern.edu/dolejsi/nsu_labs/Pressure_vs_Temperature_PhET.ziphttp://phet.colorado.edu/en/simulation/gas-propertieshttp://www3.northern.edu/dolejsi/nsu_labs/Pressure_vs_Temperature_PhET.zip


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different mathematical function and clic" again. 0hen the curve has a good fit withthe data points, then clic" .

. #aste a copy of the graph of pressure vs.temperature (3) below. The fit lines should still bedisplayed on the graph.

Pressure vs Temperature (Kelvin) for Heavy Species and Light Species gas molecules:


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PROCESSING TE DATA

. In order to perform this experiment, what two experimental factors were "ept constantC

The two experiment factors that were "ept constant were and.

/. Dased on the data and graph that you obtained for this experiment, express in words therelationship between gas pressure and temperature.

The gas pressure is to the 3elvin temperature.

1. >xplain this relationship using the concepts of the "inetic theory of gases.

The pressure is proportional to the number of molecules per unit volume and to the averagetranslational "inetic energy of the molecule. The 3elvin Temperature is a measure of

.

4. Write an equation to express the relationship between pressure and temperature (K). Use the

symbols P, T, and A.

.

8. 4ccording to this experiment, what should happen to the pressure of a gas if the 3elvintemperature is doubledC

If the 3elvin temperature is double, the pressure of a gas should .

5. 4ccording to this experiment, what changes about the graph if the mass of the species ischangedC

lic" here to enter answer.

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E!TENSION

Press"re

#$s%&"te'er%

The data that you have collected can also be used to determine the value forabsolute $ero on the elsius temperature scale. Instead of plotting pressure versus 3elvintemperature li"e we did above, this time you will plot elsius temperature on the yBaxis andpressure on the xBaxis. 'ince absolute $ero is the temperature at which the pressure theoreticallybecomes eEual to $ero, the temperature where the regression line (the extension of the temperatureBpressure curve) intercepts the yBaxis should be the elsius temperature value for absolute $ero. &oucan use the data you collected in this experiment to determine a value for absolute $ero.

. Go to #age / in Aogger #ro.

/. >nter the #ressure and elcius Temperature for the @eavy 'pecies ata 'et.

1. lic" the Ainear %it button, . 4 bestBfit linear curve will be shown for the four data points. TheeEuation for the regression line will be displayed in a box on the graph, in the form y F mx b.The numerical value for bis the yBintercept and represents the elsius value for absolute $ero.

2. #aste the graph of temperature (H) vs.pressure, with the linear fit line and its statistics stilldisplayed below. Use Text Annotationfrom theInsertmenu, to clearly label the position andvalue of absolute $ero on the graph.

6. ompare your measured value of absolute $ero with the "nown value of 9 /51 o by computingthe percent error.

error F lic" here to enter .


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Graph of Celcius Temperature vs Gas Pressure for Heavy Species:

CONCLUSION

4fter group discussion, write a conclusion summari$ing the results of this experiment.

lic" here to enter onclusion.

pressure temperature phet

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