Wednesday, June 1

Today in class we started the topic of Nuclear Bombardment. The main idea that Nuclear transmutations can occur spontaneously or artificially. If it happens artificially there is usually some form of bombardment occurring. There are many examples on page 4. We finished 1-6.

After we finished up with the packet we started on our lab. Our lab was on Radioactivity and Shielding. In it we had see what shields worked best against blocking beta particles and gamma rays. Then once we got that data we had to see which type of radiation did a better job of penetrating through the shields. After we collected all of our data we had an easy reading quiz that consisted of problems one could find on pages 2 and 3 of the packet.

Friday, May 27

We started off the class with Mr. H telling us a story about how his wife gave him a salad in a bowl giving off radiation. He then proceeded to show us by using this device [I don't know what it's called...] and pointing it at the bowl. Basically, it beeps when it detects it. He pointed it at everyone in the class and the people who were giving off a lot of radiation were Matt, Dmitry, Kevin, and Emma. Mr. H told Emma to make her own Chemistry blog because of the great blog she posted the day before. If you need a good resource, look at Emma's blog.

He then talked about how finals were in 7 days. There is going to be a review day the Tuesday before finals start.

We turned to page 1 to start off the lesson of the day. Mr. H explained to us that radiation is everywhere. Even though when the news talks about radioactive substances, it's not going to be deadly because those amounts wouldn't kill you. He gave us examples like the sun giving off radiation, but the atmosphere absorbs much of them so we aren't harmed by it. He also told us a story about a guy who took a radiation detector on his trip to Hong Kong, Japan, and back to the US and the data showed that the places the radiation detector went nuts on was when he was in the airplane. We can conclude that we are safer on the ground than in the air.

So, page 1, numbers 1, 2 and 3 were all review questions from Unit 2.

Atomic number: number of protons, identifying number

Mass number: number of protons and neutrons

Isotope: form of an atom of an element

Nuclide: nucleus of an atom

2. El is the symbol for the element

A is the mass number

Z is the atomic number or the number of protons.

This was all review so I'm not going to go over it but the answers are as follows for number 3.

Lithium-7: 3, 7, 3, 4

Carbon-14: 6, 14, 6, 8

Lead-210: 82, 210, 82, 138

Uranium-238: 92, 238, 92, 146

#4. a. 1 b. 1.5 c. 83

For number 4, you are supposed to use the chart on the right. The explanation for letter a is that when the proton count is lower(<20), there is a 1:1 ratio between the protons and the neutrons. When the proton count is higher(>20, the neutron count also gets higher. The ratio is about 1:1.5. Then, when the atomic number is at 83 or higher, the element is considered radioactive. In the chart, the elements that are not radioactive are represented by dots. When it is radio active, there are no more dots.

We turned to page 2 and worked on number 6 for the end of the class. Mr. H explained the different types of radioactive decay. Beta decay are high speed electrons and don't get through the skin. Alpha decay also doesn't get through the skin and has a helium nucleus. Positron emission is an anti electron and gamma decay is a high energy light particle. The answers go as follows:

a. beta

b. alpha

c. positron

d. positron

e. gamma

f. alpha

g. gamma

h. beta, alpha

i. alpha

j. electron capture, beta

k. gamma, alpha

l. gamma

We ended the class with that page. Have a great three-day weekend!

Salts

It's Cinco De Mayo!!!!!!!!!!


We started this class with a look at our packet to look at topics such as conjugate acids and bases to determine whether a solution is
acidic, basic, or neutral.

Let's take this reaction, for instance...
H20(l) + HF(aq) -------- H3O+(aq) + F-(aq)

We know HF is a weak acid and water can be both an acid or a base (though weak). In this case however, we know water would be the base because H3O+ is its conjugate acid - meaning it wants to give up a proton (it has that + charge it really wants to get rid of). We know the F- would be the conjugate base of HF, because F- wants to accept an extra proton (it has that - charge it really wants to get rid of). At this point you might be asking why I'm going on about this basic stuff (ba dum tss) when I could be talking about how salts dissolve. Isn't that what we discussed in class today? Why, yes it is. I am getting there.

I'll give you two examples and go through them step by step:

1. NH4Br
2. KClO4 (both of these are salts)

An aquoeous solution of a salt in water will be either acidic, basic, or neutral due to hydrolysis: either in the cation, anion, or both. Hydrolysis is when an ion reacts with water. These are ions that DO NOT hydrolize:

A. anion of a strong acid (negative charge=anion)
B. cation of a strong base (positive charge=cation)

ions that DO hydrolize:

A. anions and cations of weak acids and bases

Let's look at NH4Br again. It consists of NH4+ and Br-. Br- would not hydrolize because it is the anion of a strong acid (HBr). Therefore, you disregard it. Since NH4+ would react with water, because it is an ion of a weak acid/base, the formula would look like this:

NH4+(aq) + H20(l) -------- NH3(aq) + H3O+(aq)

We still must determine if this salt is acidic, basic, or neither. We now look at H2O. Notice how it is acting as the base in the relationship (because NH4+ is an acid). That means H3O+ would be the conjugate acid of H2O, and the conjugate acid of a weak base (such as water) would mean the salt NH4Br would form an ACIDIC solution in water.

Moving on to the next one, we see
that KClO4 would be neutral, because K+ is the cation of a strong base (KOH) and ClO4- is the anion of a strong acid (HClO4). Therefore, you can think of them as "canceling out".

You may use this logic to solve any other issue of this type you may run into. What I want you to absorb is not only that notecard you've been sleeping on, but also this:

1. Conjugate base of weak acid: basic solution
2. Conjugate acid of weak base: acidic
3. Conjugate base of strong acid or conjugate acid of strong base: neither

This is also helpful (this may be the exact same thing, but I'm not sure):

1. If cation comes from strong bas
e, and anion comes from strong acid, salt is neutral.
2. If cation is from strong base, and anion is from weak acid, salt is basic
3. If cation is from weak base, and anion is from strong acid, salt is acidic
4. If cation and anion are both weak, then you can't tell without knowing relative strengths of acid and base.

It's very much like an arm-wrestling match.


Next, we discussed how to do ICE tables for such salt equations. We were introduced to a new concept called the Kw (which is 1e-14). Basically, to find Ka or Kb of salt, you do Kw/Ka or Kb (given, opposite of what you need). You then complete the ICE table as normal. Remember that notecard with all the important conversions on it! I won't dive to deep into this because this isn't such a new concept (the notecard or the ICE table).

Then, we completed our day with a lab. Basically, this day was all about salts.


Not as unlucky as previously thought.

Monday, May 2

We did not do anything today in chemistry that was out of the normal. We learned about chemistry, and then we had a quiz. Because images make any blog post better, I found a picture of an ICE table, since ICE tables are relevant to what we are learning.












Today in chemistry we used our ICE tables to determine the pH of some acids. We started on page 7, and worked through #'s 15 and 16. To determine the pH of the acids in these problems we had to calculate the Ka value, and then use logs to find the pH. Nothing too abstract for our sophomore minds to grasp on to.
But anyway, what you really came here for. Answers to 15 and 16.

15. 5.05
16. 2.036

We flipped back to page 4, but the ICE table problems on this page are review. Nothings difficult. Grace immediately became frustrated with this, and asked if there were going to be any harder problems. This was no problem, and her frustration quickly dissolved when she discovered we were moving on. We flipped to page 8.

Page 8 was nothing special. Plain white sheet of paper, black text, the usual. I'm sure your asking yourself right now "Will, why is page 8 important?" It's problem number 19 on page 8 that's important. It captivated the entire class and left us speechless afterwards. I myself could not help but sit in my seat and gape in awe at the elegant nature of the problem. The problem required us to solve for the pH and the % dissociation of the 0.80 M solution of acetic acid. If you were able to hold off admiring the problem for just long enough to solve it, you would get a pH of 2.420 and a % dissociation of .0047. The % dissociation was much less than %, so we got by using the 5% rule to obtain a fairly accurate answer without the quadratic formula. If it was not less than 5%, than we would most likely be in an AP Chemistry class.

We finished the class today with the recently usual quiz covering current topics in class. It was very enjoyable and I can genuinely say that I enjoyed the quiz's unique option. It was 2 sided, and we were able to choose which side we wanted to do. Mr. Henderson truly is a visionary in the field of quiz making. The quiz definitely sent the class out with a bang.

*Important Disclaimer: Fabrication is evident*

Thursday April 28th

Todays beautifully short class began with going over the right column of page 5 in the packet. Mr. H. highlighted the water dissociation equation and the fact that the equilibrium of the ions is always 1.0e-14. Also that neutral solutions have equal ion concentrations, acidic solutions have more hydrogen ions, and basic solutions are just written differently and OH dominates. On the back side Mr. H. noted that when discussing powers of ions it really was just referring to the numerical value of the exponent. Below we were introduced to equations we would be using on page 6.

Next we flipped back to page 5. Mr. H. briefly spoke about number 11 which has some useful equations. He also mentioned that on a previous reading webassign there was a study tip regarding those equations:

STUDY TIP:
On a note card, write down the equations/formulas presented in these two sections of reading; these include Equation 13.1, Equation 13.2, Equation 13.3, the equation on the line below Equation 13.3, Equation 13.4, and the first equation on page 356. Keep the note card handy during class, when doing homework and when on FaceBook. Accept it as your friend.

^^^YOU HAVE BEEN WARNED

On page 6 we went over some of the table for number 12. We were able to solve columns 1 and 2 by dividing 1.0e-14 by the given OH or H3O value. The answers were for row1: 1.0e-12 row2: 1.0e-11 row5: 1.0e-7 row6: 2.0e-14 row7: 1.67e-15 row8: 2.5e-15. Next we were easily able to do columns 3 and 4 for 3 and 4. Because the pH and pOH values have to equal 14 row3: 9.00 row4: 3.00. We were also able to do column 3 and 4 for rows 1 and 2. Using our calculator we used the equations from page 26. For row 1 we took the negative log of .o1 with a base of 10 and got 2.00 for pH and 12.00 for pOH. Therefore we knew it was acidic because the pH was less then 7. For row 2 we got 3.00 for pH and 11.00 for pOH and for row 6 we got 13.7 for pH and .3 for pOH. Therefore rows 1, 2, 3, and 4 are acidic and row 6 is basic. That was the end of class.

Friday, April 15

Today we started off by flipping our packets to page 23. Mr. H said that this would be somewhat difficult, because we would have to use already learned knowledge in order to be able to work out the problems. He said that we would start out easy. The new topic that we would be learning is Ksp. It is the last topic of the unit and we should know it for the major celebration we will be having on Wednesday. Mr. H noted that if we get stuck we should look at the examples listed in our packet, which are in the book. The first thing that we did on page 23 was some review on Ionic compounds. we had to write the formulas and name the compounds. Then we had some practice with solubility and balancing equations. Mr. H also noted that when he said that there are soluble and non-soluble compounds he meant that they are partially soluble. We had some practice with this on the bottom of page 23. We then flipped to page 24, and this is what we would be putting all of those concepts together for. As I said before, Partially soluble salts dissolve only slightly in water. The dissociation of the salts are controlled by a reversible reaction that has a very small K value (much less than one). This is known as a solubility product constant (Ksp). For 4 on page 24 we had to write the dissociation equation, in which we needed to have the solubility rules. If help is needed reference example 16.1 on page 4332 in the book. After that we did some more practice on page 21 with LeChatelier's Principle. Then at the end of class we had another reading quiz which I am sure everyone did well on.

Tuesday, April 12

Today in class we continued to learn about equilibrium constant expressions. Yesterday we learned how to create Kp expressions, and today we finished learning about Kc expressions. We flipped our packets to page 12 and we worked through the page. To form a Kc expression, I will use letter c on page 12 as an example.

c. HF(aq) + H2O(l) <--> H3O+(aq) + F-(aq)

First we get rid of any substances that aren't gases or aqueous solutions. That would mean getting rid of H20(l). So now we have

HF(aq) <--> H3O+(aq) + F-(aq)

So now taking this, we place it into he equation for the Kc.


[F-] * [H3O+]
Kc = _______________

[HF]

And that is our Kc value.

I found this picture that shows the value of the Kc.

We moved in class, and added math to Kc and Kp. The only thing we changed from before, is that now the values have numbers to them. Using our knowledge of math, we plugged the equations into our calculators and got our answers. The answers o #'s 4-7 on page 13 are as follows.
4. .222
5. .00379
6. 4.315
7. .025

The next thing we did in class, was doing algebra with the constants of equilibrium. We took our equation as shown above, and we plugged in values and solved for the values we didn't have. The answers for page 14 #'s 9 and 10 are as follows.
9. 4.25 * 10^-4
10. 2.6377

Mr. H then told us that we have a quiz tommorow, and that he won't be tellling us about quizzes ahead of time from now on because we stress out less if we don't worry about it. He said we would finish the day with jokes from his jokebook, but we didn't have time. Maybe tomorrow?

Monday, February 14

We started today's chemistry class off with a little valentines day fun. Mr. H brought in a small packet, and when he hit it, a foil balloon shaped like a heart expanded inside. He explained that this was caused by the reaction of two substances, and the gas was the product. When he hit it, it reacted the two substances.

But now on to what we learned in class today. We flipped our packets to page 5 and read the first two paragraphs. This explains how electrons are configures within the orbitals of atoms. There are 2 atoms per orbital, and all orbitals in a sublevel must have one electron in them before one can have two.

We then tried some examples on the next page, I'll give you a few answers.

H 1 electron 1s1
He 2 electrons 1s2
C 6 electrons 1s2 2s2 sp1

Above this table is a diagram that shows the order of all the orbitals.

Next Mr. H taught us a shortcut. For elements that are large, and would take a long time to write out their entire electron configurations, you just put the symbol for the closest noble gas that is before the element, and then the electron configurations up to that element.
Example. For Barium.
[Xe] 6s2

Then Mr. H told us how electron configurations explain the orientation of the periodic table. I have a picture here that helps explain it.

The location of the atom determines what the last energy level will be, based on this diagram. Also, this is useful for using the shortcut.

At the beginning of class Mr. H told us we would use the computers, but we never did. I guess it took a long time to learn this. I hope we get to use the computer tomorrow!

Tuesday, January 25, 2011

This morning, we walked into class and Mr. Henderson passed out our semester grade reports. Once he was sure that everyone had received their grades, he asked us to turn to page 31 in our Thermochemistry unit packets. He gave us the answers for last night's WebAssign:
1. False
2. B
3 D
4. C
5. B
6. D
7. A
8. B
9. D
10. True
11. A, B, C
12. D, A, C, B
13. A
14. A

Subsequently, Mr. H told us to get out our lab notebooks while we looked at Daria's blog. As he read through it, he explained to us what was happening at the molecular level during state changes of water. First, the particles in the solid crystal lattice begin to vibrate when thermal energy (heat) is added (temperature increase). They wiggle more and more violently until they turn into a puddle (liquid). The fluid particles have small intermolecular forces and are relatively close together. When heat is added, they begin to vibrate and move about the puddle until so much kinetic energy is gained that the molecules "pop" out of the puddle and "fly" (as Matt said) because they are now a gas. Particles in a gas are far apart and if one were to walk through gas, there would be no resistance. Particles in a liquid are semi-close to each other and if one were to walk through liquid, there would be slight resistance. However, particles in a solid are very close together and if one were to walk through a solid...they wouldn't! Mr. H reminded us: "You can never walk through a solid."

We then turned to our TC9 lab in our notebooks. Mr. Henderson told us that we must tape our data table and graphs into the lab. We also must write a conclusion/discussion, answering all 4 questions required in a fluid manner

1. Observe the plateaus on the two graphs. What could be happening during these plateaus?

2. Determine the melting point and freezing point of lauric acid. How do they compare?

3. Describe what happens at the particle level as heat is added to the substance and its temperature increases.

4. Describe what happens at the particle level as heat is added to a substance and its phase changes.

Henderson instructed us to take some notes:

• A plateau does not equal [Delta] T
• Melting point and freezing point are the same temperature! For lauric acid, it's 44 degrees Celsius
• Plateau = mix of solid/liquid or liquid/gas

After discussing this, Mr. H gave us 5 minutes to work on the conclusion. Then, he said that there would be a demo in the back of the class later on involving boiling water and capturing the emitted gas.

Even more after, we turned to page 13 in our Thermochemistry packets. First, we did numbers 1-13:

1. D E F

2. A

3. F

4. NONE

5. A

6. D

7. D E F

8. E

[oops, where's the 9?]

10. B

11. E

12. C

13. D

The bottom of page 13 is as Mr. Henderson said "basically lab TC9" except with water. The labels for the diagram are: 1 - solid, 2 - solid/liquid (0 degrees), 3 - liquid, 4 - liquid/gas (100 degrees), 5- gas. Then, we turned to the next page (14) where we completed questions 15-28:

15. 2, 4

16. 4

17. 1

18. 2

19. 2

20. 2

21. 4

22. 5

23. 2

24. 3

25. 4

26. 1, 3, 5

27. 2

28. 4

We migrated to the back of the room to finish the demo. Mr. H connected a thin copper pipe to the flask with the boiling water. We observed as steam spewed from the end. We thought this was gas. NO! It was water!!!!!!! As the gas traveled through the pipe, it cooled back to liquid state. Mr. H then put the burner under the pipe. He showed us that this was real gas. It was SO hot that he could light a match! Then he placed a paper at the end, which he burned "I'M HOT" into. Then the bell rang.

Homework: WebAssign Due Thursday the 27th, page 15 in packet

Monday, January 10

Today we started class by grabbing our lab notebooks. We would need them for the lab that we would soon be doing. Next on our agenda, going over the webassign due today. It was a reading sheet, so we turned to page 27 (32) in our packets, and filled in the answers.

Answers:

1. C
2. B
3. C
4. C
5. B & C
6. False - The enthalpy value is relative to those values of other substances
7. B
8. A
9. To give off 185 kJ of heat
10. B
- B
- 370 kJ
- 1998 kJ
11. a. 6232.1 kJ
b. 91.0 kJ
12. D
13. B
14. D
15. 790 kJ
16. A
17. 40.64 kJ
18. (Delta)H4 = 40 kJ

Then it was time to learn about something new, Hess's law. We flipped to page 11 of our packet. Mr. H told us that this section of the unit would be one of the harder sections. But he also mentioned that it was a bit like algebra. 2 of my favorite things! Chemistry and algebra! But the way you would solve the problems went something like this.

1. Calculate (Delta)H for: 2C(s) + O2(g) --> 2CO2(g) (Delta)H = -393.5 kJ

Now to do this, we had to find a way to combine the formulas, like in algebra. In this situation, we multiplied all of the coefficients in the first formula by 2, and we flipped the second formula around making the (delta)H positive 566.

2C(s) + 2O2(g) --> 2CO2(g) (delta)H = -787 kJ
2CO2(g) --> 2CO(g) + O2(g) (delta)H = +566 kJ
and the result.
2C(s) + O2(g) --> 2CO2(g) (delta)H = -221kJ

2. Calculate (Delta)H for: 4Al(s) + 3MnO2(s) --> 2Al2O3(s) + 3Mn(s)

Now to solve this one we flipped the second formula and multiplied it by 3.

4Al(s) + 3O2(g) --> 2Al2O3(s) (delta)H = 3352 kJ
3MnO2(s) --> 3Mn(s) + 3O2(g) (delta)H = 1563 kJ
and the result.
4Al(s) + 3MnO2(s) --> 2Al2O3(s) + 3Mn(s) (delta)H = 4915 kJ

We finished the day with a lab. The lab was the "Heat of Formation Lab"
Purpose: To use calorimetry to determine the heat of formation of calcium hydroxide (knowing that the heat of formation of H2O(l) is -286 kJ)
Tomorrow in class we will discuss the calculations, but these are the results my group got.

Volume of H2O: 100 mL
Mass of Ca: 2.0g
Initial temp. of H2O: 21.6 degrees Celsius
Final temp of H2O: 53.3 degrees Celsius

And here's a picture of what the reaction looked like. It is a bit unclear, but the reaction was a bit hard to see in real life due to all the steam.











Today would not have been a very good day to miss, because I think it's we all had fun doing this lab today.

Wednesday, November 3, 2010

Today we went straight to the Math Computer Lab to work on our web assigns. To do one of the web assigns you needed to know how to balance equations and classify reactions. If you are still having trouble balancing equations then you should look at past blogs, textbook pages 60-61, and packet pages 1-4. Classifying reactions was a newer concept that I’m going to explain.

Synthesis:

· A + B = AB

· Formation of more complex compounds from simpler compounds

· Formation of compounds from its elements

Decomposition:

· AB = A + B

· Breaking down of more complex compounds into simpler compounds

· Opposite of synthesis

Combustion:

· REMEMBER O2

· Involve reaction of a substance with oxygen gas (O2)

· Some combustion reactions are also synthesis

Single Replacement

· Metal: A + BC = AC + A

· Non-metal: A + BC = BA + C

· If there is one element by itself on either side

· Replaces one of the ions in the compound

Double Replacement:

· AB + CD = AD + BC

· Compounds on both sides

· Precipitation Reaction and acid-base neutralization reactions

All this information and more can be found in packet pages 5-6. If you need additional information you can visit this site:

http://misterguch.brinkster.net/6typesofchemicalrxn.html

Thursday October 14, 2010

Today, Mr H began today's lesson by going over Matt's blog and pointing out some of the specifics that he had included such as how to do conversions and how to find the average atomic mass from multiple isotopes.

Mr. H then went over what was included in tomorrow's 90 point test. The test includes:

1) 33 multiple choice questions
2) a writing section
         a. writing formulas and names of ionic/molecular compounds
         b. a math problem like #3 on the bottom of page 14

After explaining the contents of the test, Mr. H told the class 6 different ways to study for this test. These included:

1) Looking at students' blogs from unit 2
         a. this is a good place to look, because many students have included specific formulas as well as methods on how to name ionic and molecular compounds

2) Looking at Delicious bookmarks
         a. this is also another great place to look, because not only can you study from your bookmark, but if you need help in other things from unit 2, you can study from the bookmarks done by other students

3) Looking over web assigns from unit 2
         a. This is one of the best places to look because not only can you study the answers that you got correct, but you can also study the problems that you got wrong.
                         I. in order to see the answers to the ones that you got wrong, click on the 'view key' box that is located at the top of every web assign. This box is there now, because once the due date passes for every assignment, that box pops up so students can see the answers to the questions they got wrong.

4) Looking over the unit 2 packet
          a. this is a great place to look if you are lost on certain things or if you want more practice because there are many pages filled with practice problems as well as explanations on everything in unit 2.

5) Doing the practice test that can be found on moodle. Here are the steps:
                a. Go to moodle and sign in
                b. click on Honors chem meta course
                c. under the "worksheets" tab, click on unit 2
                d. now click on the document that contains that specific thing that you want help on or want to study more. Here is the link if you are having difficulty finding it: http://gbs-moodle.glenbrook225.org/moodle/mod/resource/view.php?id=1045

6) Rereading the sections from unit 2
               a. this can be very helpful, but if you don't want to reread these sections, then i would recommend doing #s1-5

^^^^^^^ this is what the meta course page looks like after you've done all the steps ^^^^^^^^^^^


After explaining to us all the multiple ways to study, Mr. H had the class open their unit 3 packets to page 1. Mr. H went talked about all the wild conversions that we did (i.e. converting stinkups to dollars). Mr. H went on to explain that its important to be able to convert numbers no matter how wild the units are.

Mr. H then worked with the entire class to solve #4 on page 2. He explained to us that when you cancel out units, you need to make sure that you cancel the same units that are in the numerator and denominator of the problem. After canceling these units, you would multiply all the numerators together and then divide by each denominator. Here is what it would look like:

6 dopes= 11.8 napos  x 2.9 bicnics  x 17.8 blurches  = 25.4 blurches 

3 dopes      4 napos              12 bicnics

After doing this, we turned to page 4 of our unit 3 packets, and Mr. H explained to the class how atomic mass and atoms are related. For instance, if you had 24.02 amu of carbon, you would have 2 atoms of carbon. this is because 1 atom of carbon is 12.01amu. If you were to double 12.01, you would get 24.02. This is how you would solve for the number of atoms in an amu of a certain element.

For most of the day, Mr. H had gone over what the test was going to look like; that way we would be prepared for the test. Be sure to STUDY!!!!