December 15, 2009

Today, we asked Dr. B questions about everything that we covered this semester. We discussed Oxidation numbers, VSEPR Theory, London dispersion forces, and some questions on the test we had returned to us yesterday. Remember that the exam will cover each chapter evenly so don't study a certain chapter more than others. Leave comments about what else we discussed in class.

Charlie Fisher's Post

I believe that your points should not be based on how many cards that are used, but the amount of atoms used overall in the compound. I think that the one card was not necessary as their as an understood one after every element/polyatomic ion anyway. I also believe that all the candy that is brought for the group should be put into one pile and then we should use the bingo pieces as chips. This eliminates the problem of someone using a Reese's Pieces as an ante while someone else uses a kit kat. I don't agree with Michael in that we should have to name the compound in order to receive points, because many of the compounds that I created worked according to charge, but they were too complicated to name.

December 11

Percent Composition- the percent of an element found in a compound

• The percent of an element in a compound can be found using:

(Mass of the element in the sample of the compound/Mass of the sample of the compound)* 100

• The mass percent of an element is the same in a compound regardless of the size of the sample
• This can also be used for the molar mass

Mr. Scully TAKE 4

So It's the morning, and Charlie still hasn't posted. I personally won't hold it against him, seeing how his account is messed up. But I need these blog points. So I would like to say that the "1" card is a bit meaningless. In a revised edition of the game, we wouldn't need it. Also, after playing your hand, I think the player should have to name the elements in the compound in order to receive points.

Mr. Scully TAKE 3

• The Formula Poker Project was assigned today
• IMPORTANT: When faced with the question: "paper or plastic?" Answer: "Neither!" Because both are considered food, and Dr. B will nail you with a fine, whether swallowed or not.
• If wondering who's in your group, just picture yourself in Chemistry Class (scary, I know.) Who's sitting near you in the vision? Chances are, they're in your group.
• Person #1 chose how you're going about making the cards. RESPECT HIS AUTHORITY!
• Stop talking during class. 1st of all, no one cares what you have to say. 2nd of all, Dr. B gets mad and takes out her anger on certain people.
• Also, You're welcome for doing these three blogs in a row. I know you all hate posting, so I guess consider it an early Christmas Present from me.
• And another Present: NO QUIZ TOMORROW! WHOOP WHOOP! But quiz friday... AWWWWWWW.
  
• When Looking for how to get the Project sheet, Just remember 3 steps:

1. HER WEBSITE
2. HONORS CHEMISTRY
3. FORMULA PAPER

It's as easy as 123456 Pokemon. A video which you should all check out on youtube ON YOUR OWN TIME. Because right now, it's time to focus on chemistry.
POKER CHIPS=CANDY! BRING CANDY! PLEASE PLEASE PLEASE!

Mr. Scully TAKE 2

• Hey guys. I'll keep the shenanigans to a minimum today, due to request by Dr. B

• One thing to remember: If doing multiple parts to one question, don't round your first answer when applying it to the second part of the problem. YOU COULD MAKE A MISTAKE. Not that I expect that to happen. You are all very bright students: Hence the honors chemistry.

• OH! Don't forget: Finish the packet, oh ye who hath suffered lack of knowledge of its due...ness.

• Also for homework: PAGES 252-253. NUMBAS 28,29,30,31,32,and 33

• Ok, back to the information: It is useful to know the percentage by mass of a particular element in a chemical compound.

• Why? I don't know. But here's how you find it=

• % of element = 100 * (Mass of that particular element / mass of the whole compound)

• Exams are coming up, and I know studying sounds lame... but it's important.

• Yes, Michael Scully is actually telling someone to study. Shocking, I know.

• But Even Though You Want to Give up, You must KEEP ON!

• I know what you're thinking. You think that the quarter is over.
  

Over? Did you say "over"? Nothing is over until we decide it is! Was it over when the Germans bombed Pearl Harbor? Heck no! And it ain't over now. 'Cause when the goin' gets tough... the tough get goin'! Who's with me? Let's go! Ace these quizzes, Master The Material, Go Out There, And Make Yourself Proud! You've worked too hard to let the end of the quarter kill your grade. We can do this, guys. We're smart. That's why we were chosen for the Honors Track. Because the work's harder, but we can handle it! Be smart. Be strong.

Mr. Scully TAKE 1

-The molar mass of a compound can be used as a conversion factor. We said this about twenty times at the end of class today, so it must be important.
WHAT IN THE WORLD IS THE MASS OF 2.50 mol of OXYGEN GAS?!?
Don't fret my friend. It's relatively simple. 1st, realize that Oxygen exists in its gaseous state as TWO oxygen bonded to each other.
SHOCKING, I KNOW.
Buy anywho... it's just simple multiplication from here. Oxygen (or oxy, as her friends call her) has a molar mass of 16.00, roughly. Since oxy and her twin sister are hanging out together, that means we have to take 16.00 and multiply it by TWO. Now multiply that by your number of mols, and you have your answer.

so, basically just 2.50*2*16.00

BUT WAIT! HOW MANY SIGNIFICANT DIGITS DO I GO TO?!?
That's enough fretting out of you, bud. When dealing with this problem, just understand that the 2.50 mols is your estimated amount. How many sig-digs does it have? 3. How many sig-digs does your answer have? 3.

=80.0 grams. Bam, Boom, See you later.

Now as most of you remember, Dr. B flashed something about Ibuprofen across the screen for about 2 seconds at the end of class
Perhaps an exaggeration, but I reserve my creative license.
Thankfully, she pointed out to me that the problem's in the book.
<3>And seeing how you're probably already bored with my ridiculous attempts to make 5 minutes of notes in chemistry entertaining, I'll just spell the problem out for you really simply.

Ibuprofen, C13H18O2 is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol
a. If the tablets in a bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle?
b. How many molecule of ibuprofen are in the bottle?
c. What is the total mass in grams of carbon in 33g of ibuprofen?
Given: 33 g of C13H18O2, molar mass 206.31 g/mol
Unknown: a. moles C13H18O2
b. Molecules C13H18O2
C. total mass of C

Solution
a. 33g * (1 mol/206.31) = 0.16 mol (don't forget sig-digs)
b. 0.16 mol * (6.022*10^23) = 9.6*10^22
c. 0.16 mol * (13 mol) * 12.01 g = 25 g

Friday, December 4th 2009

Well not much to blog about. We played bingo and we went over the ion quiz. There will be an ion quiz Monday. Also the fall exam review as been posted on Dr. B's website. It is a very helpful study guide.

December 3, 2009

Today we played bingo, took the quiz over tables 1 and 2, and went over the test.
Begin studying for the next ion quiz
Homework: Next page in the Chapter 7 Review

December 2nd, 2009

Quiz tomorrow (Tables 1 & 2)

Formula Masses

• The mass of a water molecule can be reffered to as a molecular mass.
• The mass of one formula unit of an ionic compound such as NaCl is not a molecular mass.
• The mass of any unit represented by a chemical formula can be reffered as the formula mass.

Molar Mass

• The molar mass of a substance is equal to the mass in grams of one mole of the substance.
• The molas mass of a compound is calculated by adding the masses of the element's present in a mole of the molecules or formula units that make up the compound.
• One mole of H2O molecules contains exactly two moles of H and one mole of O atoms.
• A compound's molar mass is numerically equal to its formula mass.

Molar Mass as a Conversion Factor

• The molar mass of a compound can be used as a conversion factor to relate an amount in moles to a mass in grams for a given substance.
• To convert moles to grams, multiply the amount in moles by the molar mass.

Tuesday December 1, 2009

Tuesday December 1, 2009
For the first part of class today, we played bingo. Then we took a couple of notes:

We first did the example problem on the book on page 233-234. You can look for yourself for the work and the answers. The text does a good job at explaining it so you might wanna take a look at that.

USING OXIDATION NUMBERS FOR FORMULA AND NAMES
- Many nonmetals can have more than one oxidation number.
- These numbers can sometimes be used in the same manner as ionic charges to determine formulas.
- Suppose, for example, you want to know the formula of a binary compound formed between sulfur and oxygen. From the Common +4 and +6 oxidation states of sulfur, you could expect the sulfur might form SO2 or SO3. Both are know compounds.
- Using oxidation numbers, the Stock System, introduced in the previous section for naming ionic compounds, can be used as an alternative to the prefix system fir naming binary molecular compounds.
- An example of this is shown on page 235.

SECTION 3
- A chemical formula indicates:
- The elements present in the compound
- The relative number of atoms or ions of each element present in a compound
- Chemical formulas also allows chemists to calculate a number of characteristic values for a given compound.
FORMULA MASS
- The formula mass of any molecule, formula unit, or ion is the sum of the average atomic masses of all atoms represented in its formula.


That was it for today. Don't forget about the quiz tomorrow on table 1 and 2 and also some more info on the Chapter.
See ya