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-

Atomic Structure Review

A Sreview

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Trends in the Periodic Table

Trends

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In regards to the test tomorrow.

Well I speak for the majority of the class when I say I am lost in this unit.
Lately substitutes have been filling in but to no prevail have I learned anything because everything was just written on the board and was assumed that I knew what was being wrote.

So I'm asking on behalf of the class if Mrs. Kozoriz postpones the test till let's say, Thursday or Friday because we need some INSANE review.

Oh and get well soon Mrs. Kozoriz.

Patterns in Electron Configuration

Today's class

Ms.K hand out some worksheet today's class. one of them was pattern in electron configuration. One of the many patterns contained in the periodic table is that of electron configuration. In this activity, you will identify these patterns. Later, you will use these patterns to determine the order in which electrons fill the orbitals of an atom.

Valence electrons

Valence electrons are electrons that are in the highest principal energy level of an atom. Each of the group 1A elements has one electron in its highest energy level; each elements has one valence electron.This is no coincidence. The group 1A elements have similar chemical properties because they all have the same number of valence electron configuration of s1. Like wise, each group 2A elements has a valence electron configuration of s2. Tomorrow's scribe is Yonas

Electron Configuration

Ec

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03/10/09

TODAY'S CLASS:

Ms. K read through the GR 12 CHEMISTRY Atomic Structure: ELECTRON CONFIGURATIONS handout.

Introduced in the handout was electron configuration, being the arrangement of electrons in an atom. Atom's always want to be in their lowest-energy system possible, to remain most stable. The three rules/principles of how orbitals are filled are:

a) The Aufbau principle
- which states that each electron fills the lowest energy orbital available. For example, the aufbau diagram shows how the energy increases from 1s, 2s, 2p,3s,3p and so on.

b) The Pauli exclusion principle
- which states that a maximum of two electrons may occupy an orbital, but only if the electrons have opposite spins. The opposite spins are represented by two arrows, one pointing up, and the other pointing down.

c) Hund's rule
- which states that single electrons with the same spin must sit in each equal orbital before electrons with opposite spins can fill the same orbitals.

We also learned how to use a sublevel diagram, which will help when remembering how to fill orbitals. It is on page 2 of the handout, or uploaded below.

We were then assigned the 'Problems on Electron Configurations' on the back page.

I hope I blogged properly! Have a good night. Yonas, you can scribe

Electron Configuration

Electron Configuration

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QMM

TODAYS CLASS

Ms. K went over the answers for the sheets that were handed out sometime last week wich were:
-Atomic Structure Assignment 1 (front and back questions)
-Quantum Mechanical Model of the Atom Worksheet
-The Bohr Model of the Hydrogen Atom
The answers are on the slide show somewhere below.

NOTES

The Bohr Model of the Hydrogen Atom sheet
- An electron that occupies a higher level is said to be an excited state.
- If the electron found in the lowest possible energy level, is said to be in its ground state.

Atomic Orbitals sheet
KNOW THE SHAPES
- s orbitals give spherical clouds
- p orbitals give Dumbbell-shaped clouds

HAND OUTS

The Quantum Mechanical Model of the Atom
- note: QMM - Mathematical

Electron Configuration Polka
- a lame but educational song

Election Congfigurations
- note: 2 e- with opposite spins is written as [up arrow, down arrow] [up arrow, up arrow]

**Pick up these hand outs tomorrow of you were away today!
**Hand in the paragraph for question 8 on Atomic Structure Assignment 1 sheet tomorrow!
- Venice

NEXT SCRIBE: m;

Atomic Structure-Historical Development

Atomic Strucutre Problems

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March 06, 2009

Hello everyone.

Today at the beginning of class, Ms K showed us a slide show about the Bohr model of the atom.

I was going to post the slide show here for everyone to see but unfortunately, even with Ms K's help, there was no way.

But no worries, it turns out that one of the hand outs that we got today pretty much has all the information in the slide. This particular sheet is called "The Bohr Model of the Atom." Other than that, we got 5 other hand outs TO READ (and maybe try to work on some of them):

• The Bohr Model of the Hydrogen Atom
• Modern Atomic Theory--Energy Levels
• Development of the Quantum Mechanical Model of the Atom
• Summary: Development of Quantum Theory
• Quantum Mechanical Model of the Atom Worksheet

Lastly, Ms K gave us the rest of the period to work on the worksheet that we got yesterday, "Grade 12 Atomic Structure Assignment 1." We were told to work on both sides of the sheet but only QUESTION #8 (paragraph) is to be handed in for homework on Monday.

And I believe that's it for today.

Have a nice weekend everyone.

*The next scribe will be... BENN10

March 05, 2009

Aight so like, today, we went into class, and then the first thing we did, I think, was like.... I forgot, but anywho, we got our tests back for the redox test thingy majiggy. Anyways, after we went over the test, we started the spectrum unit thingy. Apparently, there are a bunch of atoms that have like, certain colors and stuff... And something about the number 590 and 600 etc. We got a sheet teaching us how to make dangerous explosives (fireworks) and some more sheets and stuff about the spectrum and colors and elements and their colors and stuff.
So then like, we did this other thingy, where misses teacher dude had like, this machine that makes things glow. We got these wicked sick glasses, temporarily, and used them to look at the machine which made electrons fly around inside the gas tubes, causing the atoms to get 'excited' and emit a light (chemiluminecense I believe it is called). So first we did like, Hydrogen. Hydrogen had a really cool colour thingy to it, and with the glasses you can see three lines, Red, Blue, Teal, coming from the farther away side of the atom-exciter-machine to the inwards direction (that DOES make sense). And then we looked at Helium, which was Red Orange Green and Blue, and then Iodine, which was, like, pretty much the colour of the rainbow... (ROYGBiV).
Okay so then umm... misses teacher dude decided to try some more but they didn't work. So that was a fail.
So the uhh...... sheets we got from misses teacher dude were this one sheet, about atomic structure assignment 1..... that's what it's called.... and then another sheet, which looks like a chart for spectral lines of elements, and then yet another sheet, which we were to try and fill out while looking at the atom-exciter-machine, and yet another sheet titled : The Electromagnetic Spectrum, and then a Booklet regarding The Electromagnetic Spectrum of doom (this booklet contains instructions and ingredients for making a home-made fireworks thingy). And no, we will not be doing a lab with the fireworks thing. (Dang)
And then we basically like, did stuff...... like work on that first assignment sheet, which we were supposed to read a textbook for answers I think? I don't know.

Anyways I'm done scribing.

The next scribe will be .... itscaaandy

Theeeeeeee eeeeeeend.

Rdeix Test

Redox Test

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Redox Again

Hey everybody it's night hawk here writing today's blog, the date is March 3 2009 and today we basically reviewed on how to balance Redox equations in Acidic an Basic solutions. Furthermore Ms K also assigned us page 499 questions #22 A-C in a big book as a review for our test. This basically sums up what we did today I hope everyone does a good job on the test tomorrow, well this is Night hawk signing out peace.

Redox Question 3f

3fredox

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03/02/09

Today at the beginning of class Ms.K went over the answers for the Redox Reactions Worksheet. After that we worked on Section 20.3 Balancing Redox Equations Questions 2. a-d ;HalfrxnmethodView more presentations from ekozoriz.

Today we learned that to balance a redox reactions you need to;
1. Write the oxidation numbers
2. Split the equation into two parts; oxidation and reduction
3. Add electrons to the correct sides of the equations
4. For acidic reactions add H2O and then H+ as needed
5. For basic reactions ad H2O then H+ and then OH- as needed
6. Make electrons from both reactions the same by multiplying the whole reaction
7. Add the two reactions together
8. Check that oxidation

After we finished that Ms.K assigned us Section 20.3 Balancing Redox Equations Question 3. a-f for homework and it should be done for tomorrow.