Rate Expressions and Rate Constants

Rate Expressions and Rate Constants

          To start off, Mrs. Friedmann told us she was aware of the fact that there was a field trip tomorrow and that some people wouldn't be here. Tomorrow we will be doing a lab and those not here can use the data posted by Friday's blogger. We will not be doing a write-up for this Lab

       Rate Expressions and Rate Constants packet

          We worked together on the packet we got a couple days ago. The key to what we got through today can be found on moodle here. As the packet shows, there is an easy and hard way to do Example 1A. Mrs. Friedmann only showed us the hard way so we would know how to use it. We will always be able to use the easy way for the questions we will be given.

Homework

• Complete the Rate Expressions and Rate Constants packet by Monday
• Complete the lab worksheet by Monday
• There may be Webassigns for the weekend, but if there are they won't be due until Monday night

I'm hesitant to assign a next blogger because I don't know who is and isn't going on the field trip. We'll figure it out tomorrow.

Webassign error/ score readjust

For the third webassign on the last part of the chapter, the correct answer is the one with A and C.. Although webassign marks this answer as wrong, it is the correct one and Mrs. Friedmann will adjust the scores.  Don't worry :) and good luck!

Notes on Notes

Happy Tuesday Everyone!

Today, we took the allll the notes we neglected to take on Friday or Monday. The topics were collision theory, reaction mechanisms, reaction rate and factors affecting reaction rate. I give a short summary of each of them below, but you can find the real notes at http://GBS-Moodle.glenbrook225.org/moodle/mod/resource/view.php?id=86333

Collision Theory

When a reaction takes place, it is because molecules collide with each other at 1) the right speed and 2) the right orientation. The "activated complex" is this transition stage between reactants and products during a reaction. The "right speed" is otherwise none as the activation energy.

Reaction Mechanisms

A reaction does not happen all in one go; a series of steps makes a reaction happen. The "crash" happens, and then the old bonds break to form new bonds. The overall reaction, called the complex reaction, given on paper is just the end result, and many elementary or intermediate steps are taken to get there. 

Reaction Rate

This is a measure of how quickly the reactants in a reaction become products, or how much reactant is used over time. We will calculate this in units of molarity (mol/liter) per any unit of time (seconds, minutes, etc). The elementary steps of the reaction all have different required activation energies, and the step with the highest activation energy will take the longest to complete. This is called the rate-determining step, because it will be the factor that affects the speed of the reaction.

Factors Affecting Reaction Rate

Factors include: an increase in temperature, an increase in concentration (molarity), an increase in surface area, and the addition of a catalyst. A catalyst lowers the activation energy of certain slow elementary steps and can also provide different paths for a reaction to take, making it go faster.

Homework:

Check the answers to the equilibrium packet assigned yesterday (http://GBS-Moodle.glenbrook225.org/moodle/mod/resource/view.php?id=86334)

2 WebAssigns are due on Wednesday by 11:59 pm 

Equilibrium

Equilibrium and Sub Day!

Although Ms. Friedmann was not here today to show off her amazing teaching skills, we had a "sub" in class to "substitute" for her. For the whole class period, we worked on an interesting equilibrium packet.

Homework:

• Finish the Equilibrium packet for tomorrow
• Start working on the 3 WebAssigns that are all due Wednesday

Kinetics and Equilibrium

Introduction to Kinetics and Equilibrium Unit

Friday, March 7, 2014

Today's chemistry class was all about the "It's Friday" spirit. It all started with Ms. Friedmann and Kevin G. balancing on the edge of the counter with one foot. This demonstrated holding an equilibrium…

Instead of taking notes, Mrs. Friedmann thought it would be a good idea to demonstrate some bigs ideas of this unit by doing activities in the old pit. These activities involved the class following directions:

• We tried the have a balance between two groups of people; this was done by having the same number of people on a side, making it symmetrical. 
• We tried having a group of 11 and 8 and had a flow of people traveling from one side to other other. The same number of people walking from one side maintained the balance of 11 and 8 and was not symmetrical.
• We tried having the two balanced groups of people, but everyone was moving in constant motion on each side. After walking in circles for a few moments, we had still maintained a balance.
• We tried having two groups where one group had two people walk over simultaneously with one person from the other group. This switch-up eventually led to one person on one side and the rest of the class on the other. This ended up not maintaining the balance because a different number of people from each side walked during each pass.

Lessons Learned:

• What comes in, must go out
• Equilibrium does not mean symmetrical
• Chemical reactions may appear as if doing nothing but is maintaining equilibrium
• Dynamic Equilibrium always moves, but is also always balanced

Next we went back into the class, so Mrs. Friedmann could bring fire. I left class 5 minutes early, so if anyone wants to recap what happened there in the comments, that'd be great.

Homework:

1. 2 crash course videos that you need to watch and take BIG-IDEA-ONLY notes where this should only take up 2/3 or 1 journal page for both videos 

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

1. Unlike the calendar, Mrs. Friedmann will NOT be having us do a web assign over this weekend, but will be assigned at a later date.

The next blogger is…Cool Chris

Entropy, Spontaneous Reactions, and Gibbs Free Energy

Entropy, Spontaneous Reactions, and Gibbs Free Energy
Scribe Post by Juliette O.
3/4/14

Agenda

First, we turned in the Hess's Law Lab Write Up, and for those who did not finish on Friday the Thermochemistry quiz. We then picked up the three pages of notes on Entropy, Spontaneous Reactions, and Gibbs Free Energy, and the worksheet (2 sheets) for homework. These are posted on moodle. We were reminded that the test is on Thursday-- remember to print the review packet and study it. The video is posted, and there will be a study session at 7 in the morning on Thursday. Next, Mrs. Friedmann showed us a quick demonstration on entropy and we then went over the notes. Finally, we went over the first two problems on the homework.

Notes

Homework Questions 1 and 2

Introduction to Notes

• Enthalpy is the energy in the bonds of chemicals, but enthalpy and entropy changes allow us to predict if the reactions reacts spontaneously.
• Entropy: measure of disorder in the universe, as in all the systems and surroundings 
• Processes increase disorder. 

Demonstration and Notes

Mrs. Friedmann took out a deck of UNO cards and spread them out haphazardly on the table. She pointed out that without work, someone physically organizing them, if thrown out on the table the cards are unlikely to end up in a neat stack. Work is required for that to happen. The universe is more likely to fall into disorder than order because of this. 

Order <---Requires Work-------Naturally Occurring--> Disorder

• Spontaneity=disorder, and you need work to get order.
• Example: my room had increased entropy at the end of the week! 

Mrs. Friedmann then split the deck of cards in half and put an organized half on the left side of the room and the disordered on the right side of the room. If the messy, disordered deck is on the right and the ordered deck on the left, the disordered in the products have a higher entropy. Therefore, if entropy is higher on products and lower on the reactants side, + number for delta S. 

REACTANTS --------> PRODUCTS         Spontaneous and Positive (the universe is naturally 

less entropy                       more entropy      like this b/c it is more likely to land in disorder)

more entropy                    less entropy         Negative number for delta S

• Example of a spontaneous reaction: fire burning-- it will continue burning and will light in the right conditions.
• However, many spontaneous reactions happen slowly, for example, the reactions in the body are spontaneous but occur slowly. Enzymes speed up these reactions by decreasing the activation energy in our body. Even when enzymes are involved as catalysts, the reaction is still spontaneous! 

Crash Course on Entropy:

Homework

• 3 Webassigns, two due tonight, one due tomorrow
• Worksheet (2 sheets; questions 1 and 2 done in class, 3 and 4 to be finished individually)
• Work on review packet! The video is posted on moodle.
• Study for test Thursday! Study session is at 7 AM Thursday morning. 

Heats of Reaction and Hess's Law

Heats of Reaction and Hess's Law

By: Grace Kilpatrick

Hi everyone! I hope you all are having a wonderful Thursday! Here is how class went today...

-First, Mrs. Friedmann checked in last night's homework. This was the Hess's Law-Practice worksheet and the Hess's Law worksheet, both which can be found in the Unit 8 Handouts folder. Due to time constraints, we did not have time to go over these in class. However, it is part of the homework to check the answer key to these worksheets, which is labeled as 5_Key_to_Hesss_Law_HW.pdf in the Unit 8 Keys Folder.

-Next, we went over the Heats of Reaction and Hess's Law pre-lab. These are the notes:

-For the rest of the period, we worked with a partner to collect experimental data for the Heats of Reaction and Hess's Law Lab. Mrs. Friedmann has uploaded lab data to use if you were absent in the Unit 8 Labs and Activities. This is my group's data. The upper portion is that data collected for reaction #1, where the lower portion is that data collected for reaction #2.

HOMEWORK:

-Check last night's homework with the answer keys online.

-See Webassign for the "Chapt. 9.1-2 - Solids and Liquids - Rdg Sheet" assignment due March 4th, at 11:59 PM

-Begin working on write up for today's lab-likely to be due Tuesday.

The next blogger will be...Juliette O.!