4/27 Chemistry Recording - Limiting Reagent review and Gas Law Math

https://youtu.be/cgyM5sOvpeM

Polyatomic Ions and Elements to Memorize

Hi folks,

For the polyatomic ions, the one's with the dots next to them are what you want to memorize.

Here's the list of elements to memorize. H, He, Li, C, N, O, Ne, Na, Mg, Al, Cl, Ar, K, Ca, Fe, Ni, Cu, Kr, Ag, Sn, Xe, Au, Hg, Pb, Rn, P

Also, here's the blog that has all assignments and recordings for the year.  https://2018hschemistrych.blogspot.com/

Chemistry Quizzes

Hi folks,

Here are the quizzes from this year.  I've left out the first quiz which had scientific notation and significant figures on it.  Don't worry about that for the final.

Let me know if you have any questions.

Best,

Jim Mueller

(919) 907-3217

4/26 Chemistry Update and homework due 5/4

Hi folks,

Today we took some time to discuss the final and to review another on of those pesky limiting reagent problems.  We also dove a bit deeper into the gas laws by looking at the math behind the laws.

For homework this week:

Do #'s 1, 2, 4, 5 and 9 on the enclosed worksheet.

I'm assigning a light assignment this week so that you can spend some time studying.  There will be a quiz next week which will be very similar to the quiz I just handed back, so be sure to study those names and the limiting reagent problems.  There will be some questions concerning the gas laws on next week's quiz as well.

4/19 Chemistry Class and homework due 4/26

Hi folks,

Thanks to the fact that the weather folks told us there was some very scary weather coming (turns out it was quite a bit later than they predicted) we canceled class yesterday.  However, with the video and the material in this email, I'm really hoping you take the time to get to know the gas laws and entropy.

If you feel you need more discussion of the material, this website does a decent run down of the material I talked about in the lecture.  http://chemistry.bd.psu.edu/jircitano/gases.html

This one does a nice job with the material as well.  http://physics.info/gas-laws/

For homework this week do the following THREE assignments.

In your own words, create descriptions of four of the gas laws covered in the lecture;  Guy Lussac's, Avogadro's, Boyle's, and Charles law.   Be sure to give real world situations to explain each law.  You can use the experiments we did today in class as examples if you wish.  Explain how each situation demonstrates the law.

Also, answer the following questions on entropy.

1.  What is a definition of entropy (there are quite a few…it's a messy concept)?

2.  Describe how phase change is a change in entropy.

3.  Describe how stoichiometry can show a change in entropy.

4.  If you had a certain amount of gas in a container and increased the amount of volume, how would that effect the entropy of the gas?

Also, Go to this website  http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::100%::100%::/sites/dl/free/0023654666/117354/Ideal_Nav.swf::Ideal%20Gas%20Law%20Simulation

First off, notice that for all the following scenarios you are looking at what happens to pressure as you change the variables of volume, temp, or moles (# of actual molecules).

1.  When you first load the web page, the default is "Graph pressure vs Volume (see upper left side).  

a.  What happens to the size of the container when you increase the volume?

b.  What happens to the pressure when you increase the volume?

c. What happens to temperature when you increase the volume?

d. What happens to the number of moles when you increase the volume?

e.  Of volume, pressure, temperature and moles, which are held constant?

f. Would you say that pressure and volume are proportional or inversely proportional?  In other words, do they both increase and decrease or does one increase while the other decreases?

g. Which of the laws is this representing?

2.  Now click on the temperature button and do the following questions.

a.  What happens to the pressure of the container when you increase the temperature?

b.  What happens to the temperature when you increase the pressure?

c. What happens to volume when you increase the temperature?

d. What happens to the number of moles when you increase the temperature?

e.  Of volume, pressure, temperature and moles, which are held constant?

f. Would you say that pressure and temperature are proportional or inversely proportional?  In other words, do they both increase and decrease or does one increase while the other decreases?

g. Which of the laws is this representing?

3.  Now click on the N button and do the following questions.

a. When you change N, what is changing?

b.  What happens to the pressure of the container when you increase the n?

c.  What happens to the n when you increase the pressure?

d. What happens to temperature when you increase the n?

e. What happens to the volume when you increase the n?

f.  Of volume, pressure, temperature and moles, which are held constant?

g. Would you say that pressure and n are proportional or inversely proportional?  In other words, do they both increase and decrease or does one increase while the other decreases?

h. Which of the laws is this representing?

Chemistry class CANCELLED for today!

Hi folks,

The weather is looking very scary for this afternoon and quite a few folks have contacted me concerned about class today.  So let's cancel class.  However, I have a good recording of this very class that I'd like you to watch carefully.  Please take notes just like as if you were in class.  We will do a bit more with this next week but this material will be quizzed so be sure to watch carefully.

Here's the recording.  I'll send homework later today.

Be safe everyone!

Jim Mueller

(919) 907 3217

4/12 Chemistry update and homework due 4/19

Hi folks,

This week we spent a little bit of time learning how to predict what reactants would form from what products.  We will do a bit more with this next week.  We also did a lab where we had to do a careful titration of an acid and a base in order to find how many moles of base we started with.

For homework, please answer the questions on the enclosed .pdf.  I've included answers for you to check yourself when you're done.  I've also included the lab write-up.  Last but not least, I've also included a picture of cabbage juice indicator showing what colors relate to what pH's.  

4/5 Chemistry update and homework due 4/12

Today we began a block on the chemistry of acids and bases.  We introduced the basic definitions and then did a lab where we used litmus paper 

as an indicator to find the pH of many different substances.

Read pages 308 to 330 in the Conceptual Chemistry text book.

Answer questions 1- 5 and 11 - 17 on page 332

ALSO, Answer the following questions based on today's labs. 

1.  Which two compounds could you say disassociate the most when they are put in water.  (Remember the definition of a strong acid and base.)

2.  Look up those compounds and tell me what ions are probably floating around in the water?

3.  Look up the molecular formula for rubbing alcohol.  Now that you know a bit about what makes an acid or a base, can you see why rubbing alcohol is really pretty neutral?  (Remember to think about the ions.)

Following questions relate to the dilution lab:

4.  When you diluted the vinegar, what happened to the pH?

5.  We seem to get stuck at about a pH of 3.  Do you think if we kept diluting we would have gotten a higher pH?  Do you think we could have gotten the pH to 7?  Why or why not?

6.  Why do you think adding water caused the pH to rise.  Use the words concentration and ions in your answer.

7.  Could we have gotten a pH higher than 7?  Answer: nope.  Why not???  Use the words hydronium ion and hydroxide ion in your answer.

Use the internet to answer the following questions.

4. What acids and/or bases can be found inside your body?  Name at least 4.

5.  Name at least 5 foods that are acidic or basic

Also, extra credit possibility (possible 5 points):

We tested bunches of cleaners today for their pH.  You probably found that some cleaners are basic while others are acidic.  For extra credit, do a bit of research to find out what is the chemistry behind cleaning.  Why are somethings cleaned with basic solutions while others are cleaned with acidic solutions?  Include at least two reaction equations in your paper.   I'd like this to be at least 500 words in order to get full credit.

Another extra credit possibility (possible 5 points):

We mentioned that mixing bleach with ammonia is a bad idea.  Find out why.  What is created and why is it dangerous?  You'll find this is a multi-stage reaction. Include the formulas as well as all the reactants.  There are more than one dangerous thing here so please list all of them and tell me why they are dangerous.  Is ammonia the only thing that is bad to mix with bleach?  What are some other "no-no's" and tell me why they are dangerous as well.

Recording of 4/5 Chemistry Class - Acids and Bases

https://youtu.be/6YISYFULKtg