Announcements : No Announcements Today.

Homework: None. You should have pages 1-8 already completed.

Today In Class : We did not do much in class. To start of class we grabbed pages 9-35 and taped them in our journals. The pages went about two pages per paper. Before taking the first quiz out of 7, we reviewed a little bit. we talked about how to convert grams molecules atoms and moles. We then took the quiz.

There is a total of 7 quizzes. each worth 7 points. 49 points possible. if you get 7 perfect scores you will receive extra credit. also if you receive 5 perfect you will get extra credit but a little less. same goes for 6 perfect scores. You will need to get at least one perfect score to take the end test.

To end class we had a power point on stoich. for the power point we worked on page 10.

Wednesday, January 26, 2011

Announcements : -If you have any questions about moles find Mr. Paek ( he is free 5th and 6th period.) This is a really important unit and if you want to do good on the test you have to do good on the quizzes.

-Make sure to show all work and units in homework and quizzes, because it will get very confusing later on if you don't get in the habit of doing it right now.

- Buy a notebook if you haven't already.

- First quiz tomorrow/ 7 quizzes total this unit.

Homework: -pages 7-8.

Body: Today in class we went over some problems from pages 1-6.(Again: make sure that you go get help from the TLC or Mr. Paek if you don't get something.) Then we did a lab called: Moles Stations Lab. The lab had 9 stations, and in each one of them we calculated either the mass number, mole, or the number of atoms.

Set1: had to count the number of pairs of shoes in the room.

Set2:find the mass of Aluminum foil and find its mass number and how many moles it had.

Set3:find the mass of a carbon rod find mass number of it and how moles, then how many atoms.

Set 4:we had to find how many moles of Krypton in a graduated cylinder, and the mass of it.

Set 5:we had to find the mass of H2O, and the number of grams in one mole of H2O.

Set 6:find one mole of HCl, the number of moles in it, and the number of molecules.

Set 7:found the volume of an aluminum bar its density and the number of moles and atoms.

Set 8:find the mass if neon, and the number of atoms in it.

Set 9:find the mass of a balloon and the balloon's mole.

***examples from some problems in the lab:***

set 2: 1)The mass of Aluminum foil=3.74g

2) The mass from the periodic table = 27 g/mole

3)Number of moles Aluminum foil has=3.74 g Al foil*1mole/27g of Al foil=0.14 moles of Al.

set3: 1) Mass of carbon rod= 4.35 g

2)Mass from periodic table= 12 g/mole

3)Number of mole in this carbon rod= 4.35g carbon rod* 1mole/12 g carbon rod=.36moles

4)Number of atoms in rod=.36mol*6.02E23atoms of carbon/1mole=2.16E24 atoms of carbon

Tuesday, January 25, 2011

1/25/11

Announcements - The first of quiz in this unit will be his Thursday.

Today In Class - Today in class we started by picking up some new pages for our notebooks. We then went over the lab from yesterday that was supposed to be finished for today. Mr. Paek went over some of the problems and also made sure that everyone knew what they were doing. Once we finished going over the lab, Mr. Paek showed us how to find the molecular mass of a compound. For example, the compound NH4Cl . The name of this compound is ammonium chloride. To find molecular mass of a compound, you start by finding the atomic mass of each element. In ammonium chloride, N has 14. H is one, but since there are four H's, you would really have four H. There are also 35.5 Cl. After you have found all of this, you add it all together. Once you have added it all together, you will end up with 53.5 g/mol. After we were showed molecular mass, we went over conversions one more time.

Homework - The homework for today is every problem on both page one and page two. On page three, you only have to do problem one both a and b, and problem two both a and b. On page four, you have to do all of problem three, four, and five. On page five you have to do problem one, letters e, f, g, h. The last page you have problems to do for homework is page six. You have to do problem two, letters d, e, f, and g.

THE NEXT SCRIBER WILL BE.................... yassine

1/24/11

Announcements- There will be 6-7 quizzes this unit. If you get 5-6 perfect scores then you will get some extra points added to your quiz category. Also, in order to take the final test, you must have a perfect score on at least 1 quiz you take. If you fail to do so, Mr. Paek will not let you take it with the class until you do.

Today In Class- Today in class, after rejoining us to the class again and welcoming any new students, we were introduced to the mol. A mol is 6.02 x 10 to the 23rd power. We were also told that a pair=2 and a dozen=12. Then we did a lab that worked on using Unit Analysis for finding the number of atoms in a certain number of grams, the number of grams in a certain number of mols, and the number of mols in a certain number of grams. An example of a question for finding the number of grams would be: How many grams would 3.01 x 1023 atoms of Al (26.98 grams) be? 3.o1 x 1023 atoms x 26.98 g
6.02 x 1023 atoms
Then you would cancel out atoms and do the math.

Homework- Finish the lab. We're going over it in class if you have any questions.

THE NEXT SCRIBER WILL BE....... paul mcmahon

12/8/10

Announcements

• Quiz tomorrow on balancing
• Possibly a quiz on Friday so be ready
• Test on the last Thursday before break

What We Did In Class

Today in class we first went over the homework we had the night before, which was pages 8 and 9. If you didn't do it, you probably should. It's good practice. We asked questions about it in class and got many questions cleared up. We then basically reviewed of what we learned yesterday, and elaborated more on each subject. We went over single replacement (p. 13), double replacement (p. 14), Decompostion (p. 15), synthesis (p. 16 &17), and Combustion (p. 17).

Before I describe anything we did today for you, I want you to know 1 trick that is needed every time this happens. Whenever the elements Hydrogen, Oxygen, Nitrogen, Chlorine, Bromine, Iodine, and Florine appears alone in an equation, always put a 2 after it. This is how it is used in nature so it is needed in the writing part too. A way to remember this is HONClBrIF and sound it out.

When going over single replacement, you need to find out which elements are positive or negative ions. If there are 2 positives and 1 negative, then you switch the negative from the one positive to the other. And then of course, balance it out. For example, if you had the formula: ZnS+ O2--->_____. Zn is positive, S is negative, and O is negative. So therefore, on the other side, it would be ZnO2 +S. But then you would have to balance it. So on the right side it would be 2ZnO because on the left it says there are 2 atoms of O (O2). And since I had to change that on the right, on the left it would be 2ZnS, which means on the right I would change it to 2S.

For double replacement, you do the exact same thing as single, except there will be 2 positive ions and 2 negative ions. So you would just swap them and balance them out again.

When doing decomposition, one compound splits up into 2 different ones. For example AB---> A + B. When using elements, an example would be HgO---> Hg + O2. or MgCl2---> Mg + Cl2. Make sure to balance them at the end.

Synthesis is the exact opposite of decomposition. Just put them back together. A + B---> AB. An example using elements would be K + Cl2---> KCl. Mg + O2---> MgO. Make sure that they're balanced at the end.

Finally, we have combustion. This is when there is a carbon atom, hydrogen atom, and oxygen atom all in the same equation. The answer for every single one would be CO2 + H2O no matter what. But the hard part about this is balancing them out. The easiest and smartest way to do this is by using the CHO rules. This is the order of balancing out the equation. Carbon, Hydrogen, and Oxygen. CHO. You won't forget.

Homework:

Page 10 in your journal

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THE NEXT SCRIBER WILL BE........... VIT

11-10-10 11-14-10

THURSDAY

Announcements: total review. don't forget you can drop your lowest quiz that we take.

Homework: none!!

Class: On Thursday we had a total review day. we reviewed all lewis structures, also went over homework pages 11,12,13. Then we took a quiz. after the quiz, we finished all the pages in our notebook.(up to 15) we worked on the pages all through class. most people had 10 minutes to spare at the end.

FRIDAY

Announcements:You can drop one quiz.

Homework: Finish chem think(if not finished in class) and finish the 2 practice pages.

Class: In class on Friday we went to the computer lab to work on chem thinks. The name of the chem think is "Molecular Shapes". This can be found under Covalent Bonding. It started of by explaining what VSEPR stands for. VSEPR stands for Valence Shell Electron Pair Repulsion. When you get atoms in a molecule, the bonds in the electrons repel each other. when more are added the atoms repel so they can get the furthest away from the other atoms.

While working on this chem think we had to answer a work sheet. A covalent bond is electrons being shared by two atoms. Electrons are found in the middle of the two atoms when in a covalent bond. When two atoms are bonded to a central atom the angle between them is a 180 degrees. when there are 3 is is 120 degrees. for four atoms bonded to a central atom it is 109.5 degrees.

While working with molecular shapes there are (as you can tell in the title) many different shapes. when there is just two to a bond the shape is linear. when it is in two dimensional with three atoms it is called trigonal planar. If their is a lone pair of electrons, it doesn't affect the atom but it does make the atom bent. the shape is called bent. when their is three atoms and it is three dimensional the shape is called a tetrahedral. again with lone electrons and three atoms the shape is called a trigonal pyramid.

after we finished the tutorial we moved on to the question set where you have to answer ten correct with getting 2 or less wrong. if you get three wrong you have to start over again.

Next scriber will be...... YASSINE!! (you know why)

11.9.2010

Announcements:

-During Unit 5, we will take 6 quizzes and be able to drop the lowest score.

-We took quiz #1 today.

-We will take quiz #2 tomorrow.

-We received pages 9-15 today.

Homework: Finish pages 9-15

Class: Today, we started off by doing a quick question and answer about what material was going to be on the quiz. After this, we then took our first quiz of unit 5. Once everyone had finished the quiz, Mr. Paek showed us what the answers were and went over them with us. The quiz was out of 8 total points with each question being worth half of a point.

We then started going over pages 9-15.

Page 9: This first page was Guidelines for Drawing Lewis Structures. What you first must do when you are drawing the Lewis Structures is to count the total number of valence electrons in the compound. If you are finding the structure of an ion, remember to add electrons for a negative charge and subtract electrons for a positive charge. Secondly, you should predict the arrangement of the atoms in the molecule, drawing a line to represent a single bond between each pair of bonded electrons. Thirdly, you should find the number of valence electrons left over after forming single bonds. The fourth step is to place electrons around the outside atoms until each is surrounded by eight electrons (the octet rule). H is the only element which does not follow the octet rule. The final step is to place any left over electrons around the central atom.

Page 10: Lewis Structures 1

-Ex: What is the Lewis Structure for CH4

Ans: What you would do would be to find out the needed electrons, how many electrons the compound has, how many electrons are shared, and how many bonds there are. In this instance there are 8 electrons needed for C. There are also 8 electrons needed for H4 because H needs 2 electrons and since there are 4 of the H electrons that makes 8. If you add 8+8 you will get 16. Therefore this compound needs 16 atoms. Next, is the amount of electrons they have. H4 has 4 electrons combined, and C has 4 electrons. That gives you 8 more electrons for 16. Therefore, they have 8 electrons shared. Then, you divided the shared electrons by 2 and you get the amount of chemical bonds. Then you need the formula. For this atom the formula would be H

/

H-C -H

/

H

Page 11: This is just a page of practice problems

Ex: H2O

Ans: There are 12 electrons needed, there are 8 electrons between H2 and O. There are 4 electrons shared. There are 2 bonds. Based upon this information, the formula would look like this ..

H-O-H

..

Page 12: Lewis Structures 2

Ex: Which elements are allowed to break the octet rule?

Ans: Elements allowed to break the octet rule if they do not have a full shell of valence electrons.

Ex #2: Does element A violate the octet rule?

/ / /

A

/ / /

Ans: Yes because each of those lines has two electrons in it and A would have more than eight electrons with those connected to it.

Page 13: More practice formula pages

Ex: What is the Lewis Structure for HCN?

Ans: There are 18 electrons needed, they have 10 electrons combined, therefore there are 8 electrons shared which means that there are 4 bonds. The formula would look like this:

H=C=N

Page 14: Lewis Structure 3

Ex: Draw the Lewis structures for carbon tetra-fluoride.

Ans: First you have to realize that that is CF4. Once you have done this, you can solve. Together they need 40 electrons. They have 20 electrons, this means that they share 20 electrons which comes out to 10 bonds. The formula would look like this:

.. ..

F F

/ /

C

/ /

F F

.. ..

Page 15: This is the final page of the journal and it is half of a page of practice problems.

Ex: Name the group of elements that X would belong to.

X .

Ans: X would belong to the Alkali metals group because it only has one valence electron and alkali metals only have one valence electron.

NEXT SCRIBER: JIMMY

11.8.10

Announcements:

-We picked up and taped in our calender for Unit 5

-As well as sheets 2-8

-This unit we will have 6 quizzes (and drop the lowest score if desired)

-Our first quiz will be tomorrow (Tuesday October 9, 2010)

Homework: Finish pages 2-8 (excluding page 3)

We started off by reviewing a little bit of covalent bonding (talking about where there is the least potential energy (when they are sharing electrons at a comfortable distance) and the most potential energy (when the atoms become too close so the protons of each nuclei repel each other)).

We took the rest of class to finish pages 2-8

Page 2: Questions about potential energy

-Ex: Does the potential energy increase/decrease as the atoms move closer?

Ans: Decrease as the atoms are sharing the electrons thus making their pull on them less.

Page 4: Naming Covalent Bonds Practice 1

-Ex: What is the name for the bond of CO?

Ans: Carbon Monoxide. Because there is only one carbon atom and it is the first atom named, the mono- is dropped leaving just carbon but because the second atom is oxygen and there is only one it uses the prefix mono and because the second atom should end in -ide, it becomes oxide creating Carbon Monoxide.

Page 5: Naming Covalent Bonds (2)

-Ex: CO. Ionic or Covalent?

Ans: Covalent (because it is between two non-metals) Carbon Monoxide

Page 6: Naming Covalent Bonds (3)

-Ex: Nitrogen Dioxide. Ionic or Covalent?

Ans: . NO2 (Because there is only one nitrogen it is simply nitrogen, and because there are two oxygens the prefix di- (indicating two) is placed in front of oxygen and the suffix -ide is placed at the end) and it is covalent (two non-metals)

Page 7: Naming Covalent Practice (3)

-Ex: PCl3

Ans: Phosphorous Trichloride (one phosphorous is simply phosphorous and because there are three Chlorines the prefix tri- (indicating three) is added as well as the suffix -ide)

Page 8: Naming Covalent Compounds (4)

-Ex: SiO2

Ans: Silicon Dioxide (again, one silicon is just silicon and because there are two oxygens a di- is placed in front and you get Silicon Dioxide)

10.13.10

Metal Reactivity: Periodic Trends Lab

What we did today:

First We watched videos on how the Alkali Earth metals [Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium(Francium excluded because it is illegal to obtain)] react with water. These were their reactions...

Li- Floats gives off H2 gas in reaction to water

Na- Similar reaction to water as Lithium ,but reacts more vigorously

K- Gives off flame with reaction to water

Rb- Similar to potassium ,but more violent

Cs- Cesium gives off a violent explosion with reaction to water

After the videos we were asked what trend that might be noticed as we go farther down the Alkali earth family column and the answer was they were more violent in reacting with water.

Next we were ask to describe the appearences of magnesium and aluminum.

Mg- Dull strip of metal

Al- Thin metal sheet

We were then asked what happens when they are ignited.

Mg- Sparkles with a blinding white light

Al- Shrivles

Todays Lab:

In todays lab we repeated what we saw previously in the day(combining the Alkali earth metals with water). Your data table should have similar if not the same information as the the data you collected from watching the video previous in the class period.

Post Lab Questions: (Answers)

1. Is a shiny metal more or less reactive? (Shiny metals are less reactive)

2. Which metal was most reactive in the air? (Calcium)

3. Rank the metals in order of most reactive with water to least reactive. (Ca,Al,Mg)

4. Which metal reacted to produce the most OH ions? (Calcium)

5. Rank the metals in order of most reactivity with water to least reactivity with HCl. N/A

6. Rank the four metals in this lab from the most reactivity to the least reactivity. (Ca,Al,Mg)

7. What can you conclude about the reactivity of metals as you move down a column or group? (Reacts more vigorously).

8. What can you conclude about the metals as you go across the periodic table? (More reactive)

9. N/A

Don't forget to look at your schedule to see what the homework is.

That concluded the day and the next scriber will be Brandon

PLEASE COMMENT

9.21.10

Homework Read pgs. 106-109 and complete pg. 106 #14

Today in Class

Today in class, we worked on and finished up the Atomic Scientists worksheet. We will be able to use this on the upcoming quiz, so it is important to take good notes on scientists and their contributions to the development of the atomic theory.

We were told by Mr. Paek that are goggles needed to be in Zipblock bags incase of spread of pink eye or infection. If anyone has not done so, make sure to do it tomorrow in class.

Next, we took notes on a powerpoint that was all about the four atomic scientists. The first scientist was Dalton, who in the early 1800s contributed the solid sphere model. He concluded that each element is made of atoms, atoms of one element are identical, compounds are made from different elements in whole number ratios, and that chemical reactions involve the rearrangement of atoms. The next scientist was J.J Thomson who concluded in 1897 that negative atoms must have a negative charge, and negative is negative, with overall neutrality, then must also have a positive change. He found this out by holding a magnet to sides of a tube and noticed a bend in the light. The positive side attracted the beam and the negative side repelled the beam. Another scientist was Ernest Rutherford, who in 1911 shot an alpha particle (positive charge)through gold foil. Most all went through some had deflected. He found all atoms have a tiny positive center called the Nucleus. The last scientist was Niel Bohr who in 1914 found that electrons "orbit" around. Electrons move around the nucleus in a cloud.

Pictured below are each scientist's Atomic Model

Bottom left to right:Bohr's atom, Current orbit atom

Top left to right: Dalton's atom, Thomson's atom, Rutherford's atom

Upcoming test-October 8th, lab test-October 11th

NEXT SCRIBER ..MAHAK!

9.28.10

Homework:
Read pages 101-106 in the Chemistry Text Book. There is no question today.

Class Today:
The lab today was called the "Black Box Lab." You went around the lab stations trying to find out the blockade in the black circle container. It was filled with a bead and you had to figure out the blockade without opening the box. After you felt confident in your answer you had to write the numbger of the black box down and then draw what you thought the blockade was. It was extremely confusing and difficult, often leading to extremely odd answeres from some of the class members.

This however was an extremely amazing metaphor for scientists Dalton, Rutherford, Bohr and Thomson whom all tried to decide what the shape of an atom was. They didn't have any microscopes that could see anything that tiny. Hence, the "Black Box Lab."

Reminder:
There is going to be a quiz on all four of these scientists soon. Do the worksheet assigned today that you can use on the quiz. Take notes from the four sheets that Mr. Paek gave us and you'll be good to go.

Also, the test is on Oct. 8th and the Lab test is on Oct. 11th.

Plus, if you want to retake your Lab Test, then tell Mr. Paek what day and period you're coming in.

The next scriber will be Kaylee.

Tuesday 9.7.10

Today in class, we started off by going over the basics of density (the formula and units of density). The formula for density is . In order to find mass and volume we need to know the units of mass (grams (g), kilograms (kg), and milligrams (mg)) and volume (milliliters (mL), Liters (L) and cm (cubed)). We followed this up with examples of finding density to get a better understanding for the material (Ex: If the mass of a powdered substance is 6.52 kg and the volume is 22.4 L, what is the density? You would then go on to put the mass (6.52kg) over (divide by) volume (22.4 L) and get 6.52kg/22.4L= .291 kg/L, and because it is multiplication, the answer has to match the lowest amount of significant figures, in this case, 3).

We also did an example of the different densities of substances in water and found out the a substance with higher density than all the rest sinks down to the bottom and the substance with less density than all the rest, floats to the top. All the substances in between then order themselves from top to bottom going from least dense to most dense in a totem pole looking fashion. We finished up class with a Density lab. For this lab we needed a regular object, an irregular object, a ruler, a balance and a 10 mL and 100 mL graduated cylinder.

In this lab we found the mass of a regular solid object (a metal rectangular prism) using the balance to "mass" it and the volume using the formula of Length x Width x Height. We then used these measurements to calculate the density of the solid using the equation .

To then find the density of an irregular solid object (a metal nail) we measured the mass using a balance. To get the volume we filled a 100mL graduated cylinder about half full of water. Once we measured the exact volume of the water, we added the nail and then measured the volume again. To get the volume of the nail, we subtract the initial volume of the water from the volume of the water with the nail. Once we have the mass and volume we again use the formula to calculate the density.

Finally, we measured the density of a liquid. We first measured the mass of an empty 100 mL graduated cylinder. Once we got that measurement, we filled the cylinder about one third full. We then measure the mass of the cylinder plus the liquid and then subtract the cylinder's measurement to get the mass of the liquid. We then get the volume of the liquid simply by measuring it in the graduated cylinder. Once we have the mass and volume, we calculate the density one final time by using the formula .

Our homework for tonight, is to complete pg. 9 which Mr. Paek gave out at the beginning of class to go in our notebooks. This is simply just more examples of finding the different components of the density formula ().