Wednesday 18 ,2007 ( TEST)

Hello guys . We had Kinetics Test today so nothing much to tell about. After we handed in the test, Ms. K gave to us a new Unit booklet about Chemical Equilibrium . SO yah , that's all for today scribe . The next scribe will be jhun.

Test Preparations

Today in class we went over the Reaction Rates review sheets that we were given. We were also given pages in the textbook to read in order to aid us in our test preparations, pg 395-409 in the Chemistry text book.
Next scribe is Beautiful Soul.

Last topic in Kinetics

Ms. K discussed our last topic in Kinetics and she gave us a hand out of our review sheet.
Rate law
It is an expression which relates the rate of a reaction to the concentration of the reactants.It helps us to calculate the rate of a reaction with the given concentrations of reactants.
A--->products
Rate=-ΔA/Δt
*rate of consumption a is directly proportional to its concentration,the faster a is consumed the lower its concentration.

formula: Rate=k[A]^x
where in:
k is the constant of proportionality
A is the concentration of A
x is the power,called the order of the reaction
*rate constant can only be determined experimentally
*the rate constant is specific for each reaction at a specific temperature,since its value depends upon the size, speed and types of molecules in the reaction
*TEMPERATURE is the only factor that affects the rate constant
REACTION ORDER
The order of reaction indicates how concentration of reactants affects the rate of reaction.
In a first order reaction, if the concentration of A were doubled, the rate would be doubled.If the concentration were tripled,the rate would be tripled.
Ex.
rate= k[A]²[B]³ then the overall order is 5

CALCULATING RATE ORDERS
The rate law can only be determined experimentally.Even the rate of formation of the products and the rate of consumption of reactants is related to their stoichiometry,the law cannot usually be determined from the molar coefficent.

RATE LAW AND STOICHIOMETRY
(base it on your copy,not that hard eniweys)

RATE LAW AND REACTION MECHANISM
(even this one we did this one already)
***Reminder: We will be having our test on wednesday and don't forget to answer the review sheet ok??!!!.
the next scribe would be sergio

Collision Theory and Reaction Mechanism

Hello everyOne, soRry if this blog is late...

What we did in class this morning is that Ms. K helped us to answer all the questions on the sheets the she gave to us. about potential energy diagrams and factors affecting rate. Just look at the slideshow for the answers that you didnt get..

*It sticks to my mind that the addition of CATALYST increase the rate and the activation energy become lower, like what happened to the experiment of ms. K last wednesday.

Then, she gave a new sheet about Collision and Reaction Mechanism and its glad that she explained it very clear... Like theres some new terms that we need to remember, like the

->BIMOLECULAR it means that its a combining of two particles.
->SIMPLE REACTION is the reaction which place in one elementary step.
->COMPLEX REACTION is the reaction which take place in more than one step..
Hint: all Complex Reaction contain at least one reaction intermediate.
->REACTION INTERMEDIATES products of one reaction that immediately become reactants in another reaction.
->MECHANISM is the steps in which a reaction occurs.
->RDS or RATE DETERMINING STEP the step with the slowest rate.

Ms. K also left us an assignment, just to remind you guys its assignment #4.
I didnt wrote too much because all the details is in the slideshow, just look at it.
Thenkzz...
The next scribe would be phoebes3...

Reaction Mechanism

Potential Energy Diagrams

April 10, 2007

Okay, so today in class we were given a hand out "Chemical Kinetics - Reaction Coordinate Diagrams" it basically defines the meaning of both Exothermic and Endothermic reactions.

Exothermic Reaction - In an exothermic reaction, the products possess less energy than the reactants. Also, during an exothermic reaction, heat is lost from the system and the change in heat is a negative value.

Endothermic Reaction - In an endothermic reaction, the product possess more potential energy than the reactants. This energy is absorbed from the surroundings, which increases the systems energy content. Which leads us to having a positive number when changing of heat.

Okay, now for the assignments. Just last week, we were given a yellow booklet which consisted of Kinetic Assignments 1 through 5. We were given a few minutes in class to complete assignment 2 numbers 1-3. Afterwards, we went over them.

Answers to Kinetics Assignment #2

1a. Activation Energy: 25kJ
b. Hproduct - Hreactant
35kJ - 20 kJ = +15kJ
c. This is an endothermic reaction

2a. Activation Energy: -150kJ
b. 25kJ - 100kJ = -75kJ
c. This is an exothermic reaction
d. Reverse reaction: 250kJ - 25kJ = +225kJ

3a. Activation Energy: 10kJ
b. 15kJ - 35kJ = -20kJ
c. This is an exothermic reaction
d. Reverse reaction: 45kJ - 15 kJ = +30kJ

Thats pretty much all we've done so far in the booklet.
Kay, so she also gave us a hand out of reaction rates. So just work on it.

Other then that, if you haven't completed the Kinetics Assignment (graphing) given out yesterday in class, please have it done as soon as possible.

Okay, so that's all for now. The next blogger will be yhO-eE

Kinetics

Today we went over the Kinetics Assignment #1; and then we had to do another assignment in class.
the answers for the yellow booklet assignment are:
1.a) -2.6 g/min
b)-2 g/min
2.a)-0.000013 mol/Ls
b)-0.00006 mol/Ls
c)since it's 1:1 ratio it's the same for both of them, which is 0.10 mol/Ls for CO & CH₄
3.a){basically you take the mass of beaker and contents which is given and subtract it from the first one, that's why the first square would be 0.00 and so on....}
b)0.248 g/min
c)i>0.0077 g/min
ii> -0.02167 g/min
4. for NO₂=0.2 mol/Ls
for O₂= 1 mol/Ls
5.a) 0.1125 mol/Ls O₂
b) 0.135 mol/Ls H₂O
c) 0.09 mol/Ls NO

****
Don't forget to finish the homework(assignment #1)

the next scribe is kayyy

CHEMICAL KINETICS

CHEMICAL KINETICS

Today we spend the time going over the answers of the homework(pg.424-425;Q's.17-23), and the answers should be on the blog.

Then we had a new lesson; and here are the sheets:

This is Kinetis Assignment #1 which is homework:

Answers to Kinetics Problems in text

Wednesday' class: Lab continuation

Today in chem we did another lab this time it was about how temperature affected the rate of reactions. This lab did not go so well but i knew already that the temperature does affect the rate of reactions, i think that the temperature makes everything move after therefore making reactions occur faster. Catalysts affect the rate of reaction by lowering the activation energy level and increasing the rate of reaction.
Zahra was kind enough to scribe for Thursday's class.

Factors Affecting Reaction Rates

The Scribe.. <- =D...

Well Today in class we a lab... On the Nature of Reactants..

We did part one and part two

In part one we tested the reactiblilty of certain substances in different solutions... And the time that it took for reactions to occur within those reactions...

In part two we tested on how the surface area of a substance changes the reaction rate of solutions..

It took the whole class... But we continue on with the lab tomorrow...
The End. =D

The next scribe is... gear321.

First day back from spring break

Today, our lovely chemistry teacher handed out our fire works assignments AND our tests. i hope you guys all passed with flying colors. anyways we went on reviewing the kinetics assignment that was given to us on friday of last last week. after than we were given a textbook assignment that's due on wednesday or thursday. oh and a wordsearch for fun. that is all the next scribe is ree-shard