Class blog 4/8/2014

Today we got a sheet about the 2014 GBS science contest. If you are interested in this I would talk to Mrs. Friedmann.  

QUIZ ON THURSDAY!

The quiz will be covering:

• Le Chatelier's Principle
• Ksp
• Ksp - common ion problems

We went over the solubility product constant packet as well.

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We then learned how to do common ion problems:

Solubility in water vs. solubility in another solution. 

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ex: BaSO4 <==> Ba (aq) + SO4 (aq)

                            0 M         0.10 M

                            +x            +x 

                            (x)            (0.10 + x)

Ksp BaSO4 = 1.1 * 10^-10

What is its solubnility in 0.10 M Na2SO4 solution?

Na2SO4 ==> 2Na   + SO4

0.10 M           0.20M   0.10M

1.1*10^-10 = (x)*(0.10+x)

1.1*10^-10 = 0.10x + x^2

1.1*10^-10 = x(0.10x)                                (small x rule)

x = 1.1 * 10^-9

NEXT BLOGGER: DOROTHY WASILEWSKI

Class Blog 4-7-14

Today we got back the LeChatelier's Principle Quiz back.

We did the Solubility Product of Silver Sulfate Lab today.
We did not know this was going to happen so no prep work was due today. Don't worry.

Trial One:
Initial: 17.20 mL
Final: 20.00 mL

Trial Two:
Initial: 14.30 mL
Final: 17.50 mL

Tomorrow we will be reviewing our data. There are no post lab questions.

Quiz on LeChatelier's and ICE Problems on Wednesday

Homework:
NONE!!!!!!!!!!

Tomorrow's blogger will be Harish Rajan! 

Wednesday, April 2nd, 2014

TODAY IN HONORS CHEM:

Mr. Lieberman was our sub

he didn't check in any homework

we went over the pre-lab

we did LeChatelier's Principle Lab

LAB DATA:

Test tube A: dark blue liquid, pure (transparent)

Test tube B with 1 drop of water: lighter blue

                                             B2: even lighter blue

                                             B3: EVEN lighter blue: bottom becomes light pink

                                             B4: more light pink but still some light blue

** test tube C-F have four drops of water too

Test tube C with 3 drops of HCl: even lighter blue, sky blue

Test tube D with 2 pellets of solid CaCl2: as you crush the pellets; light pink, lavender, light blue, transparent

Test tube E with 25 drops of Acetone: lighter blue, baby blue

Test tube F with 5 drops of AgNO3: thick, cloudy light pink

Test tube B in hot water bath for 2-3  minutes: dark bluish purple; turned into gas, climbed up the side of the test tube and when taken out of water, condenses and turn purple then lighter pink.

Test tube C in ice water bath for 5 minutes: turn lighter and lighter pink, very clear

HOMEWORK:

2 ICE Problem Worksheets Due TOMORROW

Post Lab:      Not a full write up

                     Type up questions and answers

                     Answer in complete sentences

                     Due TOMORROW

NEXT BLOGGER: GEMINI PLAMOOTTIL 

Class Blog April 1, 2014

In Class:

• Checked in and went over the homework that was due today (keys are posted on moodle)
• We picked up five worksheets (posted on moodle):
• LeChatelier's Principle Lab: Pre-Lab:
• Part A. Effect of Concentration
• LeChatelier's Principle Lab: Post-Lab Analysis:
• Equilibrium ICE (page 1)
• Equilibrium ICE (page 2)
• We were handed a "pop-quiz" called LeChatelier's Principle that we could work with a group, but not any notes. We did turn it in by the end of the class period

Homework

• WebAssign due tonight at 11:59pm
• We are doing a LeChatelier's Principle Lab tomorrow: Pre-Lab is due tomorrow
• Watch video on LeChatelier's Principle moodle with brief notes
• Two worksheets on Equilibrium are due this Thursday

next blogger: Francine Yoon

Class Blog 3/31/14

WELCOME BACK!!

TODAY’S NOTES 3/31/14

Le Chatelier’s Principle

Systems at equilibrium

-once something is at equilibrium you can nudge it to get it out of equilibrium

Does not like that

Textbook definition: --When a change/stress (in concentration, temperature, pressure, volume, addition of catalyst…) is applied to a system that is already at equilibrium, the position of equilibrium SHIFTS in a direction that tends to reduce the effect of that change

i.e.: -If a system is at equilibrium and you add reactants, it will shift to make more products until it reaches equilibrium again

i.e.: -If you add more heat, it will shift back to the place when it has less heat

3 Delta’s to think about:

1. Concentration

2. Pressure and volume

3. Temperature

1. Delta (change) in concentration

• When a reactant/product is added to a system that is at equilibrium, the system shifts away from the added component
• If a reactant or product is removed, the system shifts towards the removed component
• i.e. A(aq) + B(aq) → C(aq) + D(aq)
• add more A and the system shifts right to remove extra A

*Aqueous and gas rule applies

2. Delta (change) in pressure/volume

• Gas Laws:
• As volume goes down, pressure goes up (keeping temp constant)
• As volume goes up, pressure goes down (keeping temp constant)
• Systems that involve gases
• i.e.: 2A(g) + B(g) → 3C(g) + D(g)
• (3 moles reactants & 4 moles products)
• pressure increases, system shifts to the side with fewer molecules/moles of gas
• pressure decreases, system shifts to the side with more molecules

*Change of volume is “code” for change in pressure

3. Delta (change) in temperature

• Reminder: The value of k does change with temperature!
• Exothermic reaction: A(g) + B(g) → 3D(g) + heat
• As temp goes up, reaction shifts left (to try to get rid of extra heat energy)
• Endothermic: heat + A(g) + B(g) → 3D(g)
• As temp goes down, reaction shifts right

*Shifts away from thing that is making stress

Look at 4 HANDOUTS

-Intro to LeChatelier’s Principle

-LeChatelier’s Principle 1

-LeChatelier’s Principle 1 (cont)

-LeChatelier’s Principle 2

FINISHED 1st 2 worksheets in class (completed copies in notes folder)

HOMEWORK:

-Webassign due tomorrow at 11:59 pm

Finish worksheets:

-LeChatelier’s Principle 1 (cont)

-LeChatelier’s Principle 2

The next scribe: KATE MAKI

Today's Blog (3/18/14)

Tuesday, April 18. 2014!

Next Scribe: Elaine Sine

• First we checked in our graph homework. 
• Then we got back our old work (labs and worksheets).
• Then we checked over the equilibrium packet as a class.
• Then we took notes! :)

*** If equilibrium constant (K) is K > 1 then it favors the PRODUCTS, if K < 1 then it favors the REACTANTS

Today's Notes:

Chemical equilibria

(For a closed system)

Reactants ⇌ Products

• [] = means concentration (Moles/L)
• [Reactants] and [Products] never change once equilibrium is reached
• Looks like the reaction has stopped, but actually occurring simultaneously
• Closed sustems are at or apporaching equilibrium
• At equilibruim, the RATIO of [Reactants] to [Products] = constant

A⇌2B

The test is on Friday!

Joke of the day:

this one took me a while...

Homework: 3 worksheets passed out in the beginning of the class

Class Blog 3/17/14

We turned in our Alka Seltzer Lab and went over the Rate Reaction Packet. A key will be posted on Moodle.

We picked up 3 worksheets.

We divided into groups and did the Equilibrium Simulation Lab

Homework:
Graph class data from today's activity
The x-axis is Time
The y-axis is number of molecules: (atoms A/ Molecules A)

Divide the graph into two sections.

Tomorrow's blogger will be Elaine Sine 

March 13, 2014

What we did today

1. Passed out the Reaction Rate investigation sheet

2. Started the Rate expressions and Rate constants Packet

To see what we did in the packet look on the moodle page for Rate expressions and rate constants packet

Important information for the Rate law

• When calculating the rate constant (k) you don't need to worry about the units
• When finding the rate of reaction do make sure your units are correct

Hw

1. Rate expressions and rate constants packet is due Monday

2. If you're going to be absent tomorrow make sure to check the blog for the data in lab due Monday

Class Blog 3-11-14

Class Blog 3-11-14

What we did in class:

• If you were confused on the Equilibrium Packet, don’t worry.
• The Key is posted on moodle.

• Mrs. Friedmann went over what our homework was for tonight (listed below)

• We took A LOT of notes covering 5 key topics:
• Collision Theory
• Reaction Mechanism
• Reaction Rate
• Energy and the Rate Determining Step
• Factors affecting the Reaction Rate

Homework:

• 3 Webassigns, due Wednesday @ 11:59pm
• Look at the key for the Equilibrium Packet and make corrections with a different color pen
• Take a look at the first part of the packet we got in class today titled: Rate Expressions and Rate Constants

Tomorrow's Blogger: Marlye Jerva

Blog - March 7, 2014

HOMEWORK: 2 Crash course videos posted in unit 9 moodle box - watch them and take notes on them, but take big picture notes. Summarize the point of each video, notes on the big idea.

http://www.youtube.com/watch?v=g5wNg_dKsYY&feature=youtu.be
http://www.youtube.com/watch?v=7qOFtL3VEBc

(The second link on Mrs. Friedman's page was broken for me, I think the second link on this blog is the video it was supposed to be.)

MRS. FRIEDMANN DEMONSTRATING EQUILIBRIUM:

CLASS ACTIVITY IN THE PIT: This was an equilibrium and balance activity in the pit using the 21 people in our class. Many situations were posed in which we were challenged to maintain equilibrium. Here were the patterns/requirements:

1) Maintain equilibrium. To achieve this, we lined people up as tall people on the ends of the people line, moving towards the shortest person in the class in the middle.

2) Maintain equilibrium and symmetry. To get this, we split the pit in two with one person in the middle and put 10 people on each side of the pit.

3) Maintain moving equilibrium and symmetry. Same as number 2 but the people were moving.

4) Maintain equilibrium and symmetry but people moved from side to side. To achieve this, we set up like number two but sent people from side to side. As one person went to one side, a different person went to the opposite side.

5) Maintain equilibrium and symmetry moving more than one person from side to side. We did the same as number four but sent two people from side to side.

6) Maintain equilibrium but not symmetry. To do this, we had people moving randomly on each side.

END OF CLASS DEMO (WITH FIRE):