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*

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!

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.

Monday, August 30

Today in class, we started the day off by discussing the blog. He showed us the seating chart that also shows when our blog dates are, so we could remember which day we were going. Then Mr. H detailed how to log in, and how to format our posts. He proceeded to described to us how we also have to put tags in our posts, and how to put in pictures.

The next part of class today was the lecture. The lecture consisted of Mr. H telling us about Atoms, Molecules, Elements, and Compounds. He Explained how Matter consists of particles, and these particles can be individual atoms, or molecules (multiple atoms attached to each other). He also told us how atoms are elements, and that each one has it's own name ans symbol. The last part of the lecture was about how atoms can exist individually, combined with multiples of the same atom, or bonded to different types of atoms.

To finish off the day, We had a lab to do. This lab involved mixing calcium chloride, sodium bicarbonate, 5 mL of an aqueous solution, and phenol red indicator in different combinations. The groups started off by mixing all of the substances together. This produced a red liquid inside of the bag, and the bag started to inflate! This shows that the reaction was producing some sort of gas.

The next test involved mixing Calcium Chloride with the Sodium Bicarbonate. This produced no reaction for my group. Also, my group failed to complete the last part of the lab, and therefore we have no data for the last part.

Today was a very interesting day in our chemistry classroom. We learned much of the basics of chemistry, and we did a very cool lab in addition to that. I think we all had fun today.