SUMMER INSTITUTE – Module 5 – Vapor Pressure and Gas Laws
DUE by (or on) by August 2nd
***By the way we are entering the 10th week of the 1st quarter of Regents Chemistry
Module 5 notes – Vapor pressure.pdf
Module 5 notes – Gas Laws.pdf
*Connections – As we look at the phase changes we will now look at the properties of liquids and then gases. The study gases will open the door for the understanding of how we discovered that atoms existed and how they differ!! Can you imagine that we discovered how atoms “looked like” by using gases that we cannot see?!
First we will look at the property of liquids. Liquids essentially differ by the attractive forces that exist between liquid molecules. These attractive forces affect the boiling point, rate of evaporation (vapor pressure) and overall vicosity (thickness). Remember that we observed Coke being separated (distilled) based on the unique boiling point that water has and that substances in a mixture retain their own properties (like boiling point). This is how Crude oil that we get from the earth is separated into gasoline, kerosene, diesel, and many other products based on their differences in boiling points, which is due to their differences in attractive forces and how they evaporate. Later in the course we will look at why different substances have different attractive forces.
Lets introduce the concepts of vapor pressure, attractive forces, and boiling point by the 2 intro demos below:
Vapor Pressure – Force due to colliding gas molecules upwards from a liquid due to evaporation
The higher the rate of evaporation the higher the vapor pressure.
Liquid Nitrogen boils at – 196 degrees Celsius thus it boiling at room temperature which is at 20 degrees Celsius.
Boiling is a phase change that represents a liquids maximum evaporation or vapor pressure.
The liquid’s boiling point represents when the liquids vapor pressure is maximum! This maximum is attained when the vapor pressure of the liquid equals the opposing force of the pressure molecules of gas in the atmosphere (atmospheric pressure).
So in this demo we will place some liquid nitrogen into a 5 liter container and watch how the vapor pressure of the liquid will provide the force to move the flask.
When you watch these demo’s please visualize individual molecules that are colliding and causing the force!
In this demo I will place some liquid nitrogen into a paint can and hammer on a lid. The vapor pressure will win!
Activity 1: SKILL : Identify the differences in vapor pressure in liquids by observations and relate these differences to Table H in reference table.
Notes: page 25 – 27
Energy Presentation: slide 22,23 and 24.
1: Please view the smear demo.
2: Please view Table L below and observe similarities. Now we did not heat the liquids but the curves clearly show the differences in the ability of the liquids to evaporate and produce a vapor pressure.
3: Please complete the auto reply form below.
Activity 2: SKILL : Boiling phase change is a pressure dependent value.
1: Please view the lecture below that will review the basics of vapor pressure, intermolecular forces and introduce the REAL Definition of what Boiling is.
What is the Boiling point of water? You could say any temperature because it depends on the pressure pushing down on the liquid (and the attractive forces between the molecules as well).
2: Please watch the demo below on how I boil water at room temperature!! Notice the temperature of the liquid as the boiling occurs. Isn’t boiling an endothermic process? Connections!!!
3: Please view the lecture below on how to work with all types of questions that deal with table H.
4. Please complete the worksheet below and review with the key.
vapor pressure ditto 1 and 2 combined.pdf
Smear Demo with Liquid Nitrogen up against liquids in Table H:
Vapor Pressure Assessment – Please use the presentation below and the demo’s below to complete the vapor pressure quiz.
Smear Unknown Video:
Boiling Cold with Butane:
Vapor Pressure Assessment:
Activity 3: SKILL : Intro to Pressure and Manometers – devices that measure pressure
*Connections – Manometers where the first devices to measure pressure and understand pressure. The barometer, a device that measures pressure is a manometer. Many gauges that measure pressure are manometers. A sphygmomanometer below, which is what a nurse or doctor uses to measures your blood pressure is a manometer.
1: Please view the lecture on Manometers, the Manometer demo, and the Large Flask Demo.
2: Please complete the Manometers from Socrative Quiz.pdf worksheet.
3: Review the worksheet with the Review lecture below.
Large Flask Atmospheric Pressure Demo:
Why is the atmospheric pressure able to hold the cardboard against 5 liters of water in the flask? How many feet of water is being supported?
Review Lecture for the Manometers from Socrative Quiz.pdf worksheet.
Activity 4: SKILL : Observe the Gas Law Derivations to learn the 2 basic gas law formulas and all
the factors that affect gases.
1: Please view the gas law derivation lecture.
(There will be a quiz in October will all AP Chemistry students using a blank piece of paper.)
2: Please complete the worksheet below and review with the key.
Activity 5: SKILL : Combined Gas Law (Dynamic Gas Law) practice
*Connections – The combined gas law is derived from the Ideal Gas Law (Static Gas Law) and it is used primarily in Regents Chemistry. It is important to realize that every combined gas law problem could be solved using the Ideal Gas Law, but you would need to have the Ideal Gas Law Constant (R) which is not given in Regents Chemistry. The Combined Gas Law is given to you in Table T of your Regents Reference Tables.
We will spend this activity practicing our understanding of each gas variable (Volume, Temperature, Pressure, and Moles) affects gases in the Combined Gas Law Equation (which again is really the Ideal Gas Law Equation).
Now, just as the derivation lecture in activity 4 described, there must be a constant 2 variables to study the relationship between the other 2 . Lets say Temperature and Volume (Charles Law) are studied we must keep Moles and Pressure constant. I need you to think about these variables and hat needs to be constant to truly understand the following regent level problems.
1: Please view the following slides 44 – 53 and play all videos and animations in the Pressure intro presentation.
2: Then view the Boyles Law Demo and then the Boyles Law Destroyed Demo.
3: Please Complete the gas law regents level dittos 0910.pdf worksheet with the associated lecture. The math is not difficult but I need you to listen to the lectures before I go over the math, at least!
Please review with video or key. Your calculated result must mkae sense based on your understanding of gas law variables!
Boyles Law Demo:
In this demo I am lowering the moles of gas by a vacuum pump that is taking air out of the container. This will lower the pressure on the marshmallows which will Increase the Volume of air that is trapped in the marshmallows (that is why they call them puffed). Marshmallows are colliods of gas in a solid.
The number of mole of gas molecules trappped in the marshmallows are Constant.
The temperature of the gas molecules TRapped in the marshmallows are Constant.
One of the constant variables mentioned above does eventually change and the effect is reversed.
Watch when that happens.
Boyles Law Demo Destroyed by Temperature changes:
Boyles Law worksheet Review for the 1st page in worksheet:
Charles Law and Gay – Lussac Review for the 2nd and 3rd page in worksheet.
Combined Gas Law – Review for the 4th page in worksheet.
Gas Law Intro Assessment – Module 5
Please complete the Module 5 – Gas Law Intro – Module 5 assessment and enter answer into the auto reply form below.
End of Module 5