Kinetics

Notes:

For 1st order reactions [A]0/t1/2 is a constant
For 2nd order reaction [A]0 x t1/2 is a constant

Arrhenius Equation Problem

The Arrhenius equation describing the temperature dependence of the specific rate constant k for the reaction
X → Y
Use the formula: 2014-12-01_1340.png
Ignore the temperatures given and solve the equation for 500 degrees and 550 degrees.

Nuclear Fission Problem

You may use this formula for some of the problems.
K_formula.png2013-11-21_1222.png

When comparing the rate of a 1st o a order and doubling the reaction the rate = k[A][B]2
14.16.jpg



Rate_law.png
In the formula above after the = sign should be the ln[N2O5]0 not ln[N2O5]t

Rate increase

When a rate increases by a factor of:
use this to figure out the answer:
The reactant factor ^ to "X" power = the reaction rate increase

How to find the initial concentration when given the rate constant and the final concentration?
natural log of the initial concentration = natural log of the concentration at a given time + rate constant x time
ln[chemical]0 = ln[chemical]t + kt
When solving this get the number from the right of the "
=", then use inverse ln and put this number in.

first_law_%.png

For the Rate of reaction at a % complete

A 1st order reaction is 40% complete at the end of 50 minutes. What is the value of the rate constant in sec-1? In how many minutes will the reaction be 80% complete?
Answer:
[A] = [A]0 e-k’t

if A transformation is 40% complete at 50 minutes, [A]/[A]0 = .6 and t =50 minutes (3000 seconds) then k is:
(ln .6)/-3000 sec = 1.7x10-4 sec-1 at 80% completion, t is:

(ln .2)/ 1.7x10-4 sec-1 = 9467 sec (158 minutes)

For the pseudo-first-order Problem:Pseudo.png


Slope Problem:

Slope_again.png

Videos:


Part of the Kinetics unit information has moved to Chapter 16 in the new book. Page 535-544.
Read about entropy on page 546 when looking at entropy changes.
For spontaneous reaction see the chart below.
ghs.png
For more information read the following.

Vidoes:

How to find order of reaction:



Watch these Videos and answer these questions:


and these questions from 16.1 and 16.2 videos:



12.1a (Prom Date)
Intro Reaction Rates
Initial Rate Method
12.1
Integrated Rate Law
12.2
Integrated Rate Law
Catalysts/Mechanisms
12.3
Spont and Entropy
Thermo Laws
Free Energy
Calcs and Thermo
Free Energy and Eq
16.1


16.2
Kinetics Videos Calculate G H S.flv

Notes: (don't use these unless desperate.)












Labs:



Site to help with the Iodine Clock Reaction Lab.




Do Kinetics 2 instead of kinetics 6

Simulations:





Discussion

Discussion:
lpy Oct 30, 2009 8:30 am
Specific Heat is labeled c and has a chart on pg.513. Sometimes u may have to change the formulas cp=q/m*delta T and q=cp*m*delta T. Use chart on pg.529, H and S will tell if G is spontaneous. G is always spontaneous when - and not when +. -Leslie Y.
atw479 Nov 2, 2009 8:14 am

ALWAYS make sure you check out ALL charts on this chapter. Make sure your equations are balanced when you are doing problems with Hess's Law. If a problem gives you the E forward, then the E reverse is the opposite of the E forward. When solving problems with rate law sometimes plugging in numbers helps.
atw479 Nov 17, 2009 9:10 pm

These labs, to be quite honest, are not easy and sometimes are CONFUSING. You may end up having to do these labs over to get the desired results. The Equilibrium Lab is the easiest of the labs. When you come to the computer part and have to use simulations to answer the questions remember that equilibrium is reached when the numbers of the products and reactants aren't changing much. They will keep changing on the computer, but that is because a reaction is occurring constantly. The Rate and Order of a Chemical Reaction lab is harder to understand. Follow the instructions carefully to set up the colorimeter, and make sure to use potassium iodide as instructed. Leslie and I used iodine and this made our results unclear. If this solution is not in the back of the room ask Mrs. Duncan to make it for you or help you make it! The Decomposition of Hydrogen Peroxide lab is one of the more difficult labs and is time consuming, so you may want to do this one first. Make sure to follow the instructions carefully! When you set up the gas pressure sensor make sure there are no holes in the tubing. If this lab is done correctly it should have great results. ALWAYS be sure to save your graphs and any other files you make or need, and make sure you save them to the CORRECT place so they are not lost.
lpy Nov 18, 2009 8:37 am

when dealing with equilibrium lab be sure to try2 completely fill beaker without tilting large beaker the #s will be off. When doing decomposition of Hydrogen Peroxide lab check gas pressure hose for any holes or melted spots make sure stopper is on tightly Warning! It is under pressure stopper is known to pop off, watch your face. Print off all graphs in experiment and save if u run out of time Read All Instructions before you start. Any other questions ask Teacher. You may have to make your own solutions. Remember how to do molarity and % by gram

Leslie Y.
mk_2493 Dec 10, 2009 8:32 am

The black chemistry book in the back of the room on the far right bottom shelf is very helpful. The videos on this are important and make references to several charts which you can find either in that black book or in your blue chemistry book. Make sure you look the CORRECT chart to work your packet problems. There are also formulas and graphs in both books that you can use too.
Chaded Dec 14, 2009 8:20 am

The black book is very helpful especially on page 699. Kinetics is just an extension off of thermochemistry so you can use some of the same principals you learn in Thermochemistry to help you in kinetics. Good luck.
Oh, if you need help just ask Mrs. Duncan.
Chaded Jan 13, 2010 8:06 am
The kinetics labs are fairly easy especially the first one. On some of the labs you will need a certain molarity and if you don’t have it, you will need to dilute the solution. If you do not know the ratio, ask Mrs. Duncan. She will help you with it.
nchshadenj Jan 13, 2010 9:06 am

The kinetics section is similar to the Thermochemistry section. The majority of the problems are very similar to the sample problems in Chapter 17. Be sure to read everything in the chapter and look at all of the charts carefully. Some of the problems are fairly difficult, and you will need to ask Mrs. Duncan for help.
Haden J.
nchshannahw Jan 14, 2010 8:22 am
The kinetics labs can be very confusing. You should allow plenty of time to finish each lab and work out the data for the analysis. Some are VERY time consuming. If you want to do your work at home, make sure you email screen shots of the logger pro files instead of the actual files because you can’t open them on your computer at home, or at least I couldn't. It also helps to print a hard copy of each graph to have as a reference. Make sure to read and follow the directions carefully. Good Luck!
Hannah Watson
nchshadenj Feb 1, 2010 9:19 am
The kinetics labs are fairly complicated and time consuming. You will use excel to make graphs and charts on the first lab. When running experiments using Logger Pro, it would be a good idea to take a print screen of each graph. Your book will help you answer some of the questions. A lot of the information needed on the questions is found in the first paragraph on each lab. Mrs. Duncan changed the first lab to not be as much work, so if you have any questions ask her about it. Good luck with these.
-Haden J.
cas4555 Mar 23, 2010 7:51 am
Before working any of the problems in your packet, my advice is to look over Chapter 17 in both the blue and black Chemistry books. They tend to both give helpful definitions and summaries you will need to answer most of the multiple choice questions. Make sure your equations are always balanced before working! and watch your decimal answers!
Good Luck! Alex Stuart
cas4555 Mar 23, 2010 8:12 am
In the kinetics packet there is a problem that I had that needed to be modified because the book had a formula that was about .6 off which messed your answer up this formula is on page 520. The last part of the formula needs to be deleted and replaced by CH4 yields C + 2H2 and the molar heat of fusion is 74.9. If you come across this problem and you have difficulties understanding this see Mrs. Duncan for further advise.
Good Luck Caleb McKee
KatelynCheatham Mar 30, 2010 8:59 am
In the kinetics packet, chapter 17 in the blue chemistry book will help with almost all the problems. Be sure to look over all of chapter 17. However, there may one or two problems involving finding the specific rate or the initial rate. In order to learn how to work these problems, you look at the sample problem on pg. 557 of the black chemistry book (back of the room on the bottom shelf.
Good luck Katelyn Cheatham
zss262 Apr 9, 2010 9:21 am
To begin with, this was a fairly easy packet I had to reference the book, Chapter 17, a lot the sample problems at the end of each section pretty much show you exactly what to do for each problem. the solution is spontaneous if the kJ come out negative. I was partner two and this packet includes some problems asking about particular reactions and the change in the rate look at the book chapter 17 section 3 and it will explain close to what you need to know the rest you just have to use common sense and what you have learned.
Good Luck. Zachery Shuck