Kinetics Review

Kineticsreview

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Monday April 6, 2009

Today's class began with Mrs.k presenting to us several potential energy diagram on the smart board. She then went over question from the handout that was given on Friday(Reaction rates). The answers will be uploaded by Mrs.k, so no worries. we were assigned to do question 4 and b(Factors affecting rate)

Some of us worked on chemical kinetics assignment # 1, which was due today. The assignment was handed out on Thursday, the same day the hypnotist show took place. For people that were present at the hypnotist show, i believe Mrs.k is giving you more time to work on it.

i guess that's it
next scribe is robel

Reaction Coordinate Diagrams

Rxnpotentialdiagrams

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SCRIBE

Hi guys.. its me Aldrin scribing for our laaaaaasst friday class, just before spring break.:(

First thing, I'm terribly sorry for doing this scribe soooo late. I'm sure i have a reason, hopefuly:).


Here is last Friday's Scribe!!

at the start of the class Mrs' K gave us two new handouts regarding "CHEMICAL KINETICS" .
She read us through it and we learned how to differentiate an EXOTHERMIC to an ENDOTHERMIC reaction. specially using a reaction coordinate diagram.

** In an Exothermic reaction, the products possess less energy than the reactants.
During the reaction, heat is lost from the system and [HEAT(delta H) is a negative value]



**In an Endothermic reaction, the products possess more potential energy than the reactants.
This energy is absorbed from the surroundings, increasing the systems energy content.
[HEAT(delta H) is a positive value]



we also learn about ACTIVATION ENERGY(EA) - minimum amount of energy required for colliding particles to produce a chemical reaction.

after that, we answer a couple of questions regarding it.

Kinetics Assignment #2 ( 1-3)


*just remember to label the diagram properly
*locate the activation energy
and the HEAT change - whether absorbed or release
*exothermic(change in heat is a negative value)
endothermic(change in heat is a positive value)

well thats all for my scribe..
again, i'm really sorry for a very late post.
Yonas to scribe for Monday.

see you guys tomorrow. have a good night everyone!!

CALCULATING AVERAGE RATE and STOICHIOMETRY

Last Wednesday we learned about Calculating the Average Rate and reaction Stoichiometry.

AVERAGE RATE & CALCULATING AVERAGE RATE

The numerical value for the rate of a reaction can be determined by examining the change in the amount of a substance at a particular time, or over a period of time.

The average rate for a reaction is given by the following equation:

The following is an example of calculating the average rate of a substance:

What is the average rate over the entire 27 seconds?

Rate = X ÷ T

Rate = (Final concentration of X) - (initial concentration of X)
               ______________________________________
               final time - initial time

Rate = (1 mol/L - 0.0 mol/L)/(27 s - 0 s)

Rate = 1 mol/L ÷ 27 s

Rate = .037 mol/Ls

RATE AND STOICHIOMETRY

Rate of creation of products or disappearance of reactants can be predicted from reaction stoichiometry.

We'll use 2NO2 ---> 2NO + O2 as an example

The rate of decomposition of NO2, is equal to the production of NO. The ratio is 1:1. This shows that as one molecule of NO2 is decomposed, one molecule of NO is produced.

The rate of production of Oxygen is half that of the NO. The ratio is 2:1. The rate production of NO should be twice that of the oxygen.

Therefore,

On the same day Mrs. Kozoriz handed out some worksheets and here are the answers for Questions 1 - 3

Ask Mrs. Kozoriz for the work sheets if you missed Wednesday's class.

ALDRIN to scribe for Friday

Tuesday, March 24,2009

Hi classmates
This is Yassir scribing for Today's class.... This will be a short scribe because it was just a work period. We had to finish the FACTORS AFFECTING THE RATE OF A REACTION-STUDENT EXPERIMENT from the lab. And if you haven't done the lab today was the chance. Lab is due tomorrow.

If i forget to say anything else please go to Ms.k, because i don't remember anything else except lab,that's only what i remember.

NEXT SCRIBE is BooM

Niwatori-san's Corner (Kinetics intro)

In the past class before the Chemistry lab in which labeled "Factors Affecting the Rate of a Reaction"

We were introduced to the Kinetics unit.

A handout was handed out to display terms we should know.

Such terms included:

Rate
Rate is the speed in a chemical reaction of the reactants amount of products made.
This is usually observed experimentally by a certain chemical property.

The measurement of Rate can be varied depending how and what is being measured for the chemical reaction.

Here's a definition briefing of the terms that can be used to measure rate.

Temperature
Temperature is labeled (ºC/min)
While the reaction is on going the temperature increases. If heat is produced at a fast rate then the a higher rate for the chemical reaction will occur.

Pressure
Measured in (kPa/s or mmHg/s)

The more GASEOUS CARBON made in a chemical reaction the more the pressure increases giving an increase in rate.

Mass
In the form (g of C/min)

In a chemical reaction, with more reactants being used up and converted to gas; resulting in a loss of reactants/increase in mass of the product

Other
Other forms that rate can be label are colour change, pH change, change in conductivity, and etcetra etcetra over period of time. All are a change over time since the rate is determined during the experiment is undergo

-Quoting the text handout-
"Rate is usually described in terms of change in concentration of reactant or product over time." =)

Rate can be found from this formula in question :
RATE = change in concentration
change in time




And that concludes that class haeng un (korean for good luck) in your future studies

Niwatori-san signing off Yassir to scribe for Tuesday's class

"Close encounters are the best for finding a solution/comfort without and casualty"
-Niwatori-san-