Archive – AP Chem – Q2 – week 9 – 21-22

Q2: Week 9 – 1/17 – 1/21

Jump to: Tuesday, Wednesday, Thursday, Friday

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1/17 – Monday – Martin Luther King Day –

I have a dream that one day this nation will rise up and live out the true meaning of its creed: “We hold these truths to be self-evident, that all men are created equal.”

I have a dream that one day on the red hills of Georgia, the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood.

I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice.

I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.

I have a dream today!

I have a dream that one day, down in Alabama, with its vicious racists, with its governor having his lips dripping with the words of “interposition” and “nullification” — one day right there in Alabama little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers.

I have a dream today!

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1/18 – Tuesday – B Day – 2, 3b/4 Lab

Main focus –

a) To compare and contrast phase diagrams of water and carbon dioxide.

b) To review Stoichoimetry and collection of a gas by water displacement

c) To Derive the kinetic molecular theory formulas.

d) To list the Kinetic Molecular Theory requirements for an Ideal gas (student).

Period 2:

1. Review the homework:

Gas Law Stoichiometry key p.pdf
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2. Phase Diagrams Lesson, refrigerators, air conditioners (did not quite get to this)

Phase diagram review:

a) Critical Point

b) water vs. carbon dioxide

c) Freeze dried / astronaut food

d) ICE SKATING/ the titanic.

3. Kinetic Molecular Theory Gas law Derivations – Take notes, quiz on this tomorrow! You may need to complete this using the video below.

Kinetic Molecular Theory Classwork Derivation.pdf

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In your reference Tables:

Period 3/4:

1. Same as above – except we will complete the kinetic molecular theory derivation.

2. Lab 19 – Boyles Law Syringes – Its the error in this lab that will incorporate the kinetic molecular theory that we are deriving!

LAB 19 – Boyles Syringes Lab.pdf

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Notes for Phase Diagram:

Water Phase Diagram:

Comparison or water to carbon dioxide:

Use For Phase Diagram lesson:

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1/18 – Tuesday Homework: –

We are moving into the last topic of Gas Laws.

We have been describing how the different variables affect each other with the derivation of our gas laws but we have not explained why gases behave this way. Gas behavior is explained through the Kinetic Molecular Theory and it is best understood through ANOTHER Derivation!!

1. Please watch me derive the Kinetic Molecular Theory formulas in the video below IF YOU ARE IN THE PERIOD 2 class as we did not finish the derivations completely. Take notes and follow along with me. You can use the quiz that you will have tomorrow as you guide.

START THE VIDEO AT 24:00 which will pick up where we left off in class FOR BOTH CLASSES!!

I will give you the assumptions, Governing Equations, and the symbols.

I will give you some of the derivation in a skeleton format to help you complete it.

Video of Grodski completing the derivation:

START THE VIDEO AT 24:00

2. Study the derivations as you will be given a quiz tomorrow on the derivations. I cannot believe that am doin this but here is the quiz that you will take tomorrow:

Kinetic Molecular Theory Classwork Derivation.pdf

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1. Kinetic Molecular Theory Derivations:

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1/19 – Wednesday – A Day – A Day – 2/3a Lab, 4

Main focus –

a) To demonstrate how to derive the molar KE formula and the root mean squared velocity formula from governing equations.

b) To identify the Gas Law Constant needed for KMT equations requires a different constant.

Period 2/3:

1. Review the Kinetic Molecular Derivations. I will review both derivations BEFORE your quiz as you did not get the LIVE version for the second derivation yesterday.

2. Take the KMT Derivations quiz

3. Review the different R constant needed for KMT equations = JOULES!!!!

4. Perform Lab 19 – Boyle’s Law Syringes.

LAB 19 – Boyles Syringes Lab.pdf

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Period 4:

1. Take the KMT Derivations quiz

2. Review the different R constant needed for KMT equations = JOULES!!!!

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Kinetic Molecular GAS law Constant (R) NOTES :

In Kinetic Molecular Equations – (Used to help describe why gases behave according to the ideal

gas law and all of its derived equations: M = dRT & d = PM

P RT

Kinetic Molecular Equations are centered around Kinetic Energy formula, KE = 1/2 mu²

and thus are centered around the SI unit of energy = Joule.

Thus our Kinetic Molecular equations must have terms or units that reflect equivalents in Joules.

Remember from experimental evidence PV = nRT or R = PV

and we have been using .08206 (atm L)

(mole K)

as our Gas Law constant (proportionality constant) and you have learned that you must be in same units for your variables as your ideal gas law constant, R otherwise units do not cancel and your calculation will be in error.

In Kinetic Molecular Equations we cannot use this value of R

that has uses Pressure (atm) and Volume (V) in its Numerator.

We need a value of R that uses Joules instead in order to reflect the KE that is part of the derived Kinetic Molecular Equations that we derived.

KE per mole = 3/2 RT Urms = √3RT

Molar Average KE Root Mean Squared Speed M

This R cannot be the same value as we have been using as it needs to reflect Joules (Energy).

Well fortunately, P x V (the numerator in R) actually can equal Joules if we change the units of

Pressure from atm to Force/Area and Volume from L to meter³ (length x width x height):

Force = mass x acceleration due to gravity

Kg x meter/sec²

Area = meter²

P x V = Energy

force/area length x width x height

Force x meter³

meter²

( Kg x meter/sec² ) x (meter³ ) = Kg meter² = Joule

meter² sec²

So with our Kinetic Molecular equations we use R = 8.31 J _

mol K

This is given in our reference tables:

Also because a joule is really a Kg meter² / sec² then M must be in Kg!

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1/19 – Wednesday Homework: –

1. Please complete just the front page of the Gas Law worksheet 6 – kinetic energy-grahams law.pdf worksheet.

2. Review with the key but I suggest you follow along with me in the video below.

Gas Law worksheet 6 – kinetic energy-grahams law.pdf
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Gas Law worksheet 6 – KEY- kinetic energy-grahams law.pdf
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2. Front page of the Kinetic Energy – Grahams Law worksheet:

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1/20 – Thursday – B Day – 2, 3b/4 Lab

Main focus –

a) To Review the concepts of the molar KE and Root Mean Squared Formulas

b) To derive the Grahams Law of Diffusion and Grahams Law of Effusion through root mean squared.

Period 2: –

1. Review the 1st side of the homework.

Gas Law worksheet 6 – KEY- kinetic energy-grahams law.pdf
View Download

a) model first problem on backside of last nights homework

2. Derive the Grahams Law of Diffusion and Effusion.

2 gases at the same temperature and thus the same Average Molar KE:

KE = 1/2 m µ²

Gas A: 10000 J = 1/2 (2 Kg/mol) (100 m/sec)²

Gas B: 10000 J = 1/2 (200 Kg/mol) (10 m/sec)²

3. Graham’s Law of diffusion Demo’s

a) HCl vs NH₃

b) Manometer with He and SF₆

c) Demo Graham’s law effusion and diffusion of the 2 balloon in class.Amazing Grace – speed of sound

3. Grahams Law Demos with balloon and manometer.

Period 4: –

1. Same as period (1,2,3)

2. Lab 19 Start.

LAB 19 – Boyles Syringes Lab.pdf

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So after today we now have another gas law equation in our reference tables:

Grahams Law which is really root mean squared:

Grahams Law of Diffusion of HCl and NH₃ Demo:

Grahams Law of Diffusion of HCl and NH₃ Demo 2:

Manometer of He and SF₆ Demo:

Amazing Grace of He and SF₆ Demo:

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1/20 – Thursday Homework: –

1. Please complete the second side of the Gas Law worksheet 6 – kinetic energy-grahams law.pdf

worksheet.

2. Review with the key.

*At 20:30 of the lecture posted last night I reviewed the first problem on the second side.

Gas Law worksheet 6 – kinetic energy-grahams law.pdf
View Download

Gas Law worksheet 6 – KEY- kinetic energy-grahams law.pdf
View Download

3. Complete the form below:

3: Kinetic Molecular Theory Form::

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End of Thursday!

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1/21 – Friday – A Day – A Day – 2/3a Lab, 4

Main focus –

a) To Review Grahams Law of Diffusion (Effusion).

a) To compare and contrast phase diagrams of water and carbon dioxide.

Period 2/3: –

1. Review the Grahams Law homework, video of HCl and ammonia.

2. Perform Lab 19 – Boyles law syringes.

3. Start the review of the errors in terms of REAL Gas Behavior

Period 4: –

1. Review the Grahams Law homework and form.

2. Perform Lab 19 – Boyles law syringes.

One of the Errors in the Lab 19:

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1/21 – Weekend Homework: –

Lab 17, 18, and 19 did not have conclusions (initially) but I am asking that you write them and attach them to your labs. I should have handed your labs back to you. (I was afraid some of you would lose them if you held onto them too long).

Now the errors in these labs are all based on simple idea that all gases do not behave like the ideal gases. This means that the gases in the labs that we used were placed in formulas that ASSUMED IDEAL GAS BEHAVIOR BUT no gas is completely ideal. This means that there will be some deviation from OUR DERIVED GAS LAWS!!!! OUR calculations will be off by some amount due to:

1. The gas particles ARE NOT completely random and do not move in straight line motions (actually curved!!)

2. The collisions are not completely Elastic (they actually stick together a little bit)

3. The gas particles DO ATTRACT each other a little bit.

4. The Gas particles DO HAVE some volume!!!

1. Please watch the Real Gas Law demo below to view an example of a calculation of gas pressure that is higher than expected to the above listed NON-Ideal conditions:

2. Please watch the Gas law Error Review video to apply these errors to your labs. Write a conclusion for each lab based on the REAL GAS behavior of the gases that were investigated. Attach to your lab and hand in MONDAY!

REAL Gas behavior Demo with calculation:

Gas Law Lab Error Review:

End of week Nine!