AP Chem – Q2 – week 7 – 21-22 | Mr. Grodski Chemistry

Q2 : Week 7 – 1/2- 1/6

<Week 6 – Week 8> Jump to: Tuesday, Wednesday, Thursday, Friday

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If you have not already please join the REMIND for this class.

Please Make sure Your read all instructions for all assignments.

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1/2 – Monday – New Years Day Observance

^{_________________________________________________} Jump to: Tuesday Homework / top 1/3 – Tuesday – A Day – 2/3a Lab, 4

Main focus –

a) To introduce the concept of Stoichiometry through gases.

b) To learn of the story of Torricelli and the birth of the manometer.

c) To measure pressure with a manometer

Period 2/3a:

1.Review the Volumetric Titration Tests –

Volumetric Titrations and Spectrophotometry 1 test key.pdf
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Volumetric Titrations and Spectrophotometry 2 test key.pdf
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2. Connections of our last learned concepts to our new concept of gas laws.

3. Manometer introduction – The first measurement of pressure.

– definition of pressure – bed of nails demo = P = F/A

– Lungs / Syringes / Pistons / Nothing sucks!!! – Just high pressure moving to low pressure due to pressure changes.

showed how area changes can affect Pressure quantities for intro to Boyles Law

Period 4:

1. Same as above except the review of the last test will be tomorrow.

Gas Law Segway:

In lab 16, we dissolved the brass shot with nitric acid. The balanced reaction that you needed for the lab is given below:

You can see that the product of the reduction of the nitrate ion (NO3- ) is NO2 which is released as a brown gas. Let’s take a look at the time lapse of this reaction.

Lab 16 oxidation of Cu and Zinc in brass:

Could we have measured the amount of NO₂ gas collected and through stoichiometry determined the amount of copper in the brass, skipping the spectrophotometer entirely?

YES!!! We can use the volumes measured through gas generating reactions to…

1. determine the limiting reagent 2. Determine the amount of the reagents ( amount of active ingredients, % by mass ) 3. Determine the empirical formula? (mole ratios of atoms. 4. identify the compound (molecular mass. 5. Determine the Amperage needed to power this non-spontaneous reaction?

In how many reactions that we witnessed or discussed in class up to this point did we generate a gas? Did we generate a gas in electrolytic cells? Did we split water using an electrolytic cell?

I did this demo in class.

What does the amount of the gases generated above tell use about the chemical formula of water?

In the above demo, I mixed the buffered solution (at pH = 7) with Universal Indicator. Universal indicator has the following pH values based on pH:

Does the color changes in the different test tubes with the different electrodes match the half reactions? Acid/Base connects with redox and now gases can connect to both (all concepts).

I conveniently dismissed the amount of gas generated in all of our reactions till NOW! What labs did we do that generated gases that we could used for stoichiometry?

How about the last one?

Gas Laws begin– measuring gas pressure all started with the story of Torricelli

He developed the concept of manometer to solve the problem of the water well in Tuscany Italy.

A water well that brought water to the city state of Tuscany was recently moved inside the city walls, which had a higher elevation than where it once stood. The well’s hand crank could not deliver any water when it was in the cities walls but worked outside the city states wall.

By solving this problem he developed the first way to measure and quantify pressure.

Gas Law Pressure Intro Presentation:

Nitric Acid and Copper demo with gas law implications.

Manometer demo explained through demo:

Connections and the Torricelli Story: Today’s lesson

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1/3 – Tuesday’s Homework: –

1. Please complete the lecture above if necessary– Story of Torricelli continues –

Manometers introduction with worksheet:

Please start at 43:17 if you need review of measuring pressure with the physical manometers (non- word problems).

Gas Law worksheet 1 – Manometers.pdf
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Gas Law worksheet 1 key – manometers.pdf

View Download 2. Please complete the entire Gas Law worksheet 1 – Manometers.pdf, including the word problems using the video posted below. Sometimes manometer problems present themselves in hidden ways.

A review of the word problems of the Manometer worksheet:

End Of Monday!!!

_______________________________________________________________________ Jump to: Wednesday Homework / top 1/4 – Wednesday – B Day – 2, 3b Lab/4

Main focus –

a) To identify the units of pressure and their equivalents

b) To derive the ideal gas law equation and the combined gas law equation.

c) To introduce the Universal Gas Constant.

Period 2:

1. We will review the Manometer homework, especially the word problems. a) water demo /cardboard/large Flask.

b) Examples of Manometers – gauge pressure (view the back) / sphygmomanometer demo –

c) Nothing sucks, suction cups, discussion of straws, Romans hiding in river with Reeds

2. To derive the Universal Gas Law Equation – You will have a quiz on this derivation in the near future.

Period 3/4b:

1. Complete the story of Torricelli and the water pump

a) Nothing sucks, suction cups, discussion of straws, Romans hiding in river with Reeds

b) Examples of Manometers – gauge pressure (view the back) / sphygmomanometer demo –

2. We will review the Manometer homework, especially the word problems.

a) water demo /cardboard/large Flask.

3. To derive the Universal Gas Law Equation – You will have a quiz on this derivation in the near future.

Derivation Notes:

Static vs. Dynamic Gas Law Derivations- first of many!

A) the Ideal Gas Law formula: PV = nRT

(Static Gas Law formula)

B) the Combined Gas Law formula: P₁V₁ = P₂V₂

(Dynamic Gas Law formula) ^_____^_____

T₁T₂

_{The Temperatures must be in an absolute scale that measures the degrees away from a true zero to be able to correctly measure the change in gas variables.}

Combined Gas law Formula animation:

Gas Law Derivation animations:

Large Flask Demo from past years:

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1/4 – Wednesday Homework: –

1. a) Please watch the last few minutes (from 13:50 on) of the gas law derivation posted below.

(In both classes I did not quite finish it with Combined Gas law formula.)

b) Complete Gas Law worksheet 1.pdf and review with the key.

– now you are applying the 2 gas law equations, Do I use the dynamic or static?

Gas Law worksheet 1 -.pdf
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Gas Law worksheet 1 key -.pdf

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2. Complete the Gas Law worksheet 2 worksheet and review with the key or lecture below.

Gas Law worksheet 2.pdf
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Gas Law worksheet 2 key.pdf

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1: Gas Law Derivation Video:

End Of Monday!!!

2: Gas Law worksheet 2 Review:

End Of Monday!!!

_________________________________________________________________________ Jump to: Thursday Homework / top

1/5 – Thursday – A Day – 2/3a Lab, 4

Main focus –

a) To have guided practice with the Ideal Gas Law Equation and Combined Gas Law

b) To identify Gas Law problems in other “Units”.

c) To identify the individual relationships between gas variables.

Period 2/3a:

1. Review the last nights Homework –

a) identify the formula used – Last night’s Homework review – When to use Dynamic or Static

b) cancelling the correct units

c) Notice that 22.4 L = 1 mole in question 4

d) relationships in last question of second worksheet

Question 4 – of Gas Law worksheet 2.pdf

2. Review of variable relationships from derivation – (draw graphs for period 2 in derivation)

– relationship only works when other variables are held constant

3. Demonstrations using the relationships: Some will be very Cool, cryogenics fluid explained.

Proof that pressure – support of column of water, Large Flask

*Remember n = moles, T is always in Kelvin!

Charles’s Law: V = T x K₁

Volume and Temperature – Balloon/money

Avogadro’s Law: V = n x K₂

Volume and moles – vapor pressure – Paint Can

Boyles’s Law: V = 1/P x K₃

Pressure and Volume – Marshmallows/shaving cream, Tornado tubes.

Gay Lussac’s Law: (Implied from the other relationships above) P = T x ( constant T, constant n)

Pressure and Temperature – Air Horn

absolute zero demonstrator

4. Started Homework, gas law regents level dittos 0910.pdf

New pressure – unit Kilo pascals – from pressure intro presentation

Period 4:

1. Same as above but will not finish all demos and will not get to start tonights homework.

Volume and Temperature (K) are proportional: Charles Law

Volume and moles are proportional: Avogadros Law

Volume and Pressure are inversely related : Boyle’s Law

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1/5 – Thursday Homework: –

1. Please view page 2 of the Pressure Intro Presentation (re-posted below) it derives for you the kilo pascal pressure (our 4th). Currently we have the following equivalent units of pressure:

Standard Pressure = 1 atm (atmposphere) =

760 mm Hg = 760 torr =

14.7 psi (pounds per square inch) =

101.3 kPa (kilo Pascals) → you will see this in Regents Chemistry

2. Please complete following worksheet and review with the key.

This might be collected at some point in the near future.

You may wonder why we are doing this worksheet now. It will makes sense when you complete it:

Please use the following half reactions for the following worksheet:

O₂(g) + 4H⁺ + 4e^– → 2 H₂O(l) 1.23 v

2H₂O(l) + 2e^– → H₂(g) + 2OH^– -0.83 v

Intro Electrolytic Cells worksheet 3.pdf
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Intro Electrolytic Cells worksheet 3 key p.pdf
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3. Please complete the gas law regents level dittos 0910.pdf worksheet and review with the key.

We started this in class and remember to use you understanding of the relationships of the ga

variables to check if the answer makes sense.

gas law regents level dittos 0910.pdf
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gas law regents level dittos 0910 key.pdf
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Gas Law Pressure Intro Presentation:

Liquid Nitrogen and Hot water = FOG!!!

Bernoulli Bag Demo = organizing air and creating a lower pressure (partial vacuum) in front of balloon.

__________________________________________________________ Jump to: Friday Homework / top 1/6 – Friday – B Day – 2, 3b Lab/4

Main focus –

a) To Derive the standard unit of Pressure = Pascals

b) To Derive the density and Molecular mass of a gas

Period 2:

1. New pressure – unit Kilo pascals – derivation from pressure intro presentation

2. Boyles Law demo with Tornado tubes – Final relationship with 1st derivation – (make graph)

a) Boyles Law destroyed with liquid nitrogen – gauge pressure – Cracking knuckles, using a straw, fish face!

3. Ideal Gas Law Relationship – egg in and out of the bottle – Both ways

4. New Derivation of Density and Molecular Mass of a Gas

Period 3b/4:

1. Same as above, include shaving cream demo, racket spheres

2. Determination of Absolute zero activity – possibility

Boyles Law Destroyed by Temperature:

Egg in and Out of the Bottle – Traditional Demo

Egg in and Out of the Bottle – Liquid Nitrogen Demo

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1/6 – Weekend Homework: –

1. Complete the Gas Law Stoichiometry Density 2009 worksheet below and review with the key below.

This is actually a FRQ from 2009 using a Lab and our derived gas law formulas. Although it is a lab that we have not done (next week!) it is very simple. There are no grodski twists here. Just a pure AP College Board question complete with its key explaining points earned. See how many points you would off earned on this question. This will be collected Monday!

Gas Law Stoichiometry Density – 2009.pdf

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Gas Law Stoichiometry Density – 2009 AP Key.pdf
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2. Please study the Ideal Gas Law Derivation and the Molecular mass/Density Derivation for tomorrow’s Quiz. I have posted both derivation video below for your review.

You will be asked to derive:

A) the Ideal Gas Law formula: PV = nRT

B) the Combined Gas Law formula: P₁V₁ = P₂V₂

^_____^_____

T₁T₂

C) The Molecular Mass formula: M = dRT

D) The density formula (from the above formula) d = (solve from above)

I cannot believe that I am doing this but I am going to release the quiz Before you take it!!! Here it is!

Gas Law Equations Derivation Quiz.pdf
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3. Please complete the following worksheet that is based on the newly derived Molecular Mass and Density equations and review with the key below:

This will be collected Monday as well!

Gas Law worksheet 5 – density, MM, Stoich.pdf
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Gas Law worksheet 5 – density, MM, Stoich KEY.pdf
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End of week 7!

Ideal Gas Law Derivation Video:

Molecular Mass and Density Derivation Video: