It is seriously freezing out here. Please. It's not even close to absolute zero yet! Absolute Zero (Gay-Lussac’s Law) 012-10730 r1.04

It is seriously freezing out here.

Please. It's not even close to absolute zero yet!

Absolute Zero (Gay-Lussac’s Law) 012-10730 r1.04

The Snapshot button is used to capture the screen.

The Journal is where snapshots are stored and viewed.

The Share button is used to export or print your journal to turn in your work.

IntroductionJournals and Snapshots

Note: You may want to take asnapshot of the first page ofthis lab as a cover page for your Journal.

Each page of this lab that contains the symbol

should be inserted into your journal. After completing a lab page with the snapshot symbol, tap (in the upper right hand corner) to insert the page into your journal.

Absolute Zero (Gay-Lussac’s Law)

Lab Challenge

Temperature is a measure of the average kinetic energy (motion) of molecules. As the temperature of something drops, the motion slows down. Things can’t move slower than stopped. Does this mean there is a lowest possible temperature and if so, what is this temperature?

Hot air molecules move fast!

Cold air molecules move slowly.

What happens when air molecules are very, very, very, very, very, very, very cold???


Background

• Gas molecules move through space, bumping into things. This causes air pressure. The more collisions there are each second, the more pressure there is.

• Temperature is the average kinetic energy (speed) of the particles in a sample.


Self-Check

1. Pressure is caused by the collision of gas molecules with ______________.

a) higher volume

b) liquid molecules

c) the walls of the container

d) motion

e) excessive homework


...Background

• Kinetic energy is related to the speed of the molecules, so if the temperature increases, the molecules move faster.

• An increase in speed will cause gas molecules to strike the walls of the container more times per second, so the pressure increases.

• The direct relationship between pressure P and temperature T was discovered by Joseph Gay-Lussac in 1802. Gay-Lussac's law is expressed mathematically as:

more collisions = higher pressure


(constant) ORkT

P

2

2

1

1

T

P

T

P

Self-Check

2. If you decrease the temperature of a gas inside a container, what happens to the gas particles?

a) They exert higher pressure.

b) They increase in kinetic energy.

c) They decrease in speed.

d) They increase in speed.


...Background • If it were possible to continue to remove kinetic energy by cooling, there

should come a point where the gas particles would be so cold they would have no kinetic energy at all!

• If particles have zero kinetic energy, they are no longer moving and, therefore, are not able to collide with the walls of the container to create pressure.

• This theoretical point at which kinetic energy has been completely removed from a system (particles stop moving and the pressure equals zero) is known as absolute zero.


...Background

• Because temperature is a measurement of molecular motion (kinetic energy), the Kelvin temperature scale sets the point of no kinetic energy as its starting point, 0 K.

• This means that the Kelvin scale has no negative values.

Boiling point of water

Weather: highest temp. recorded in the world

Freezing point of water

Weather: lowest temp. recorded in the world

Moon at its coldest

Absolute zero


Self-Check

3. The Kelvin temperature scale is based on ___________________.

a) molecular motion

b) the freezing point of water

c) the boiling point of water

d) the coldest temperature ever recorded


...Background

• Absolute zero can be calculated experimentally using Gay-Lussac's law to find the relationship between pressure and temperature. The relationship can then be used to calculate temperature (absolute zero) when the pressure equals zero.

• Gay-Lussac's law can be rearranged to give the familiar equation of a straight line:

• There is one small catch, Gay-Lussac’s law requires that the temperature measurements be in Kelvin.


kT

P kTP

mxy

Self-Check

4. When using Gay-Lussac's law, the value for temperature must always be measured in ______.

a) ˚F

b) kPa

c) ˚C

d) K


kT

P

Safety• Follow all common laboratory procedures.

• Be careful with hot water! Water at 65˚C (149˚F) has enough kinetic energy to damage skin and eyes.

HOT!!


Materials and EquipmentCollect all of these materials before beginning the lab.

• Sensor extension cable

• Absolute pressure sensor

• Quick-release connector

• Tubing connector

• Fast response temperature sensor

• Tubing, 1- to 2-cm

• Test tube, 15-mm x 100-mm

• One-hole stopper for test tube

• Beakers (2), 250-mL


Materials and EquipmentAlso collect these additional materials before starting.

• Polystyrene cups (2)• Rubber band• Ring stand• Three-finger clamp• Crushed ice (300 mL)• Room temperature water, 300 mL• ~45˚C water, 300 mL• ~55˚C water, 300 mL • ~65˚C water, 300 mL • Glycerin, 2 drops


Glycerin

The steps to the left are part of the procedure for this lab activity. They are not in the right order. Determine the correct sequence of the steps, then take a snapshot of this page.

Sequencing Challenge

A. Place the closed test tube in a polystyrene cup containing ice-water and record the pressure and temperature.

B. Set up the equipment to measure pressure and temperature of air trapped in a test tube.

C. Graph the data and use the equation of the line of best fit to determine absolute zero.

D. Replace the ice-water with water at 25 ˚C, 45 ˚C, 55 ˚C, and 65 ˚C. Record the pressure and temperature for each.


*To Draw a Prediction: 1. Tap to open the tool

palette.2. Tap then use your finger

to draw your prediction.3. Tap when finished.4. If you make a mistake, tap

to clear your

prediction.

Q1: What will happen to the pressure in the test tube as temperature increases? Draw your prediction on the graph provided.*

PredictionAbsolute Zero (Gay-Lussac’s Law)

Setup

1. Connect the fast response temperature sensor to the data collection system.

2. Connect the absolute pressure sensor to the data collection system using a sensor extension cable.

Extension cable

Pressure sensor


3. Connect the quick-release connector to the stopper using the tubing connector and the 1- to 2-cm piece of tubing. Put a drop of glycerin on the connectors as necessary.

Q2: Temperature and pressure are being measured for what substance during this experiment?

Setup

Tubing connectorQuick-releaseconnector

Tubing Stopper


Q3:The temperature sensor is placed on the outside of the test tube. Is this a problem? Explain.

Setup

5. Use a rubber band to attach the quick-response temperature sensor to the outside of the test tube. The sensor should be about halfway down the test tube.

Rubber band

Temperature sensor


4. Use a rubber band to attach the quick-response temperature sensor to the outside of the test tube. The sensor should be about halfway down the test tube.

Setup

6. Attach a three-finger clamp to a ring stand. Use the three-finger clamp to securely hold the absolute pressure sensor in a vertical position.

7. Place the polystyrene cup into a 250-mL beaker. Fill the polystyrene cup to the top with ice. Add water to make an ice bath.

Q4: Why is a polystyrene cup used instead of just a beaker?


SetupQ5a: What is the dependent variable (with units) in this experiment?

Q5b: What is the independent variable (with units) in this experiment?


Setup

8. Place the beaker containing the polystyrene cup and ice-water underneath the absolute pressure/test tube apparatus and slowly lower the test tube into the ice-water.

9. Angle the test tube in the cup so the entire test tube is covered with the ice-water. Place more ice on top of the test tube to ensure that the entire test tube is covered with ice.

Q6: Why is it necessary for the entire test tube to be covered with the ice-water?


Procedure1. Tap to start a new

data set. 2. Wait ~2 minutes to allow

the temperature of the air in the test tube to become the same temperature as the ice water surrounding it.

3. Tap to record the temperature (in ˚C and K) and pressure.

4. Remove the test tube from the ice water bath.


Procedure5. Place the second

polystyrene cup into the second 250-mL beaker.

6. Fill the polystyrene cup with water at room temperature (~25˚C).

7. Angle the test tube in the cup so it is covered with water.

8. Wait ~ 2 minutes.9. Tap to record the

temperature and pressure.


Procedure10. Collect three more data

points by replacing the room temperature water with water at:

~ 45 ˚C~ 55 ˚C~ 65 ˚C

11. For each sample wait ~ 2 minutes and then tap to record the temperature and pressure.

12. When all five data points have been collected, tap to stop the data set.


Data Analysis1. Using the data collected,

derive the mathematical equation used to convert between the Celsius and Kelvin temperature scales.


*To Apply a Curve Fit: 1. Tap to open the tool

palette.2. Tap to open the Curve

Fit screen. 3. Tap the name of the curve

fit required.

Data Analysis2. Create a best fit line (linear

fit) of data using the ˚C values for T.*

Note: the equation of the best fit line gives:

P = kT (y = mx )


Data Analysis

3. Use the equation of the best fit line to solve for absolute zero in units of ˚C. Show your work.

Hint: Absolute zero is the temperature when pressure equals zero.


Data Analysis

4. Calculate the percent error of your experimental value of absolute zero (the accepted value of absolute zero is -273.15˚C). Show your work.

percent error =(accepted value - experimental value)

accepted valuex 100


*To Enter Data into a Table:1. Tap to open the tool

palette.2. Tap then tap a cell in

the data table to highlight it in yellow.

3. Tap to open the Keyboard screen.

5. Determine the constant k for the five data points collected using Kelvin temperatures. Enter the constants into the table.*

Data AnalysisAbsolute Zero (Gay-Lussac’s Law)

kT

P

Data Analysis6. Determine the constant k

for the five data points collected using ˚C temperatures. Enter the constants into the table.*


*To Enter Data into a Table:1. Tap to open the tool

palette.2. Tap then tap a cell in

the data table to highlight it in yellow.

3. Tap to open the Keyboard screen.

kT

P

1. Was pressure divided by temperature a constant when using temperature values measured in ˚C? Why or why not?

Analysis2. Was pressure divided by

temperature a constant when using temperature values measured in K? Why or why not?

3. Are pressure and temperature directly or indirectly proportional? How do you know?


Analysis4a. What is the Kelvin temperature scale

based on?

4b. What is special about 0 K?


Analysis5. Calculate the pressure of the air inside the test tube if it were warmed to

100.0 °C. Show your work (there are several steps)!


Synthesis1. Another lab group did the same

experiment using a syringe instead of a test tube. Could this cause a problem? Explain.


2. Explain why an over-inflated tire may pop when it is driven fast on a hot day.

SynthesisAbsolute Zero (Gay-Lussac’s Law)

Multiple Choice

1. Which of the following graphs best represents the relationship between the pressure of a gas and Kelvin temperature?


A)

D)

B)

C)

Multiple Choice2. Why does pressure become zero at a

temperature of absolute zero?

a) At absolute zero all molecular motion stops.

b) At absolute zero there is a complete vacuum.

c) At absolute zero the gas volume is very small.

d) At absolute zero all the energy of the gas is given off as light.


Multiple Choice

3. What is the equivalent of 413 K in Celsius?

a) -273˚C

b) 0˚C

c) 140˚C

d) 696˚C

e) 237 K


Multiple Choice

4. If a container of gas is at a temperature of 27 ˚C and a pressure of 800 torr, what would the pressure of the gas become if the temperature were doubled to 54˚C?

a) 1600 torr

b) 400 torr

c) 872 torr

d) 734 torr


Multiple Choice

5. If the temperature of a gas in a closed, rigid container decreases, the pressure inside this container will _________________.

a) increase

b) decrease

c) stay the same

d) Either A or B depending on the type of gas.


You have completed the lab.Congratulations!

Please remember to follow your teacher's instructions for cleaning-up and submitting your lab.


All images were taken from PASCO documentation, public domain clip art, or Wikimedia Foundation Commons.

1.PENGUINS http://www.openstockphotography.org/image-licensing/penguins/Adelie_penguins_at_Cape_Geddes_Laurie_Island_1962.jpg

2.THERMOMETER http://www.freeclipartnow.com/science/thermometer-big.jpg.html3.FLAMES http://www.freeclipartnow.com/science/energy/Flames-1.jpg.html4.ICICLE http://www.freeclipartnow.com/nature/weather/icicles.jpg.html5.SNOW FLAKE http://www.freeclipartnow.com/nature/weather/snow/snow-flake-shadowed.jpg.html6.STOP SIGN http://www.freeclipartnow.com/small-icons/miscellaneous/stop-sign.jpg.html7.WEATHER http://commons.wikimedia.org/wiki/File:Mistral_wind1.jpg8.BALLOONS http://www.freeclipartnow.com/recreation/partying/balloons-01.jpg.html9.HOT WARNING http://commons.wikimedia.org/wiki/File:DIN_4844-2_Warnung_vor_heisser_Oberflaeche_D-

W026.svg10.EYE WASH http://commons.wikimedia.org/wiki/File:Sign_eyewash.svg11.BEAKER http://www.freeclipartnow.com/science/flasks-tubes/beaker-2.jpg.html12.CRUSHED ICE http://commons.wikimedia.org/wiki/File:Hail_001.JPG13.GLASS OF WATER http://www.freeclipartnow.com/food/beverages/glass-of-water.jpg.html14.CALCULATOR http://www.freeclipartnow.com/education/supplies/simple-calculator-01.jpg.html15.TWO GAS CYLINDERS

http://commons.wikimedia.org/wiki/File:Compressed_gas_cylinders.mapp_and_oxygen.triddle.jpg

ReferencesAbsolute Zero (Gay-Lussac’s Law)

Documents

It is seriously freezing out here. Please. It's not even close to absolute zero yet! Absolute Zero (Gay-Lussac’s Law) 012-10730 r1.04