5/10 Chemistry Update

Hi folks,

Today we spent the entire day reviewing a variety of concepts that we covered throughout the year.

No homework this week, just study those old quizzes and try to master as much as you can for the final exam.

Let me know if you have any questions or need any help.

Good luck everyone!

Best,

Jim Mueller

(919) 907-3217

One more worksheet

I missed this one in the first batch.  This is also not homework, just a great sheet to practice with.

5/3 Chemistry update and homework due 5/10

Hi folks,

Today we touched on how temperature, phase change and heat energy are all interrelated.   We may do more with this next week depending on how much time we spend doing review for the final.   

My camera gave up the ghost this class I'm afraid so there is no recording.  I'm sorry about that.

Next class will be review so spend the time this week going over old quizzes and seeing if there are some areas that you have questions on.  Next week I'll spend as much time as we need to cover old material.

For homework this week take a look at the enclosed .pdf called Predicting Reaction Products.  Do all the questions included in the worksheet.  Answers are available for you to check yourself.

I've also included a bunch of worksheets for you practice with.  All of these cover material that will be on the final so it may well be worth your while to practice with these.  They are NOT homework just another way for you to master those chem skills.  

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

3/29 Chemistry Recording

https://youtu.be/fINxOq7E5ic

3/29 Chemistry Update and homework due 4/5

Hi folks,

This week we took a look at the concept of concentration. Basically, how many particles of something is in a solution. We worked a few molarity problems and some concentration problems. Then we did a fun lab where we used these concepts to discover what molarity of lemonade tastes the best.

For homework please do the enclosed worksheet. Several of these are two step problems so you need to convert to moles first. Answers are included so you can make sure you are on the right track.

Also, please answer the following questions regarding the lab. Answers below.

1. The lemonade container had a mass of 536g. How many moles of lemonade was in the container (just use the molar mass of sugar, C12H22O11, for the molar mass of lemonade)?

2. How many particles of "lemonade" is in the container (in other words, convert moles to particles)?

3. You've discovered that .25 M is the perfect molarity for a perfect tasting lemonade. You are having a party and want to impress all your friends, so you need to make 3 liters of lemonade. What mass of powder would you need? You need to convert moles to mass here. (See, and you thought chemistry wasn't useful.)

4. Whoops. .25M is way too sweet. Let's dilute that to .2M. How much water do you need to add. Use C1V1 = C2V2 here.

5. If you poured the entire jar, all 536g of lemonade, into a 2.2 liters (a gallon) jar, what would the molarity be?


Answers:
1. 1.57 Moles

2. 9.4 x 10^23

3. .25 = m/3 .75 moles so .75x 342 g/mol = 256.5g

4. C1V1 = C2V2
.25 x 3 = .2 x V2
3.75L = V2 So you need to add .75 L of water to dilute it.

5. 1.57/2.2 = .71M (That might be a bit sweet.)

3/22 Chemistry Class update and homework due 3/29

Hi folks,

This week we took some time to see what is required to make reactions happen and what can be done to influence the rate of reactions.

We also took the time to do a fun brainteaser lab where the students were required to separate a mixture into its component parts using only one "tool" per separation. We then found the percentage composition of the materials in the mixture.

For homework this week:

Read pages 271 - 288 in the text.

Do Review Questions 1 - 28 on pages 301 and 302 (Many of these are review from earlier in the year)

3/22 Chemistry Recording - Reaction rates

https://youtu.be/2DxX-ZsLMC0

3/15 Chemistry update and Homework due 3/22

Hi folks,

Today we took the time to take a look at the entire year.  I find that students are so busy learning new thing, after new thing, after new thing that they don't really have the chance to put things in context or perspective, so I like to take some time every now and then to unpack what we've learned and take another look at it.

We also learned some vocabulary to classify different substances. 

For homework this week:

Read pages to 37 - 62 in the text.  Much of this will be review.  

Answer questions 1 - 22 on page 64 (No Math!!!!)

3/15 Chemistry Class Recording - Review of the Year and Classifying Substances

https://youtu.be/LTGYXSTxgPQ

Extra Credit possiblility

Hi folks,

Here's an extra credit possibility.   I'll give you one point of extra credit for every item in the shopping list you get right.

Also, don't forget the other extra credit possibilities.  10 points of extra credit if you recite the periodic table.  10 points if you can give me the name/symbol for every element on the periodic table.  10 points for reading the Disappearing Spoon and answering questions about it.

Good Luck!

3/1 Chemistry update and homework due 3/15

Hi folks,

Today we spent a small amount of time reviewing some of our recent problems and then introduced the concept of percentage yield.

For homework this week I'd like you to:

1.  Do the .pdf called "Questions for Limiting Reagents Lab".

2. To practice more of these, I've included  "Limiting Reagents and Percentage Yield Worksheet."  I've included the answers in there for you as well.

Spring Break!

Hi folks,

Just a reminder that this is spring break week for Science Jim classes.   No classes from March 4 to March 8.

Enjoy the break everyone!

Best,

Jim Mueller

(919) 907-3217

2/22 Chemistry recording - Limiting Reagents

https://youtu.be/v9HtPoJPMM0

2/22 Chemistry Class and homework due 3/1

HI folks,

Today we took a look at our last step in the world of stoichiometry which is limited reagents.  We also did a fairly fast but interesting lab where we found how much carbon went into and came out of a reaction with sulfuric acid and baking soda.

Here are a couple of videos to help you if you need it.  One is the video we saw in class today and the other is the same fellow solving a limiting reagent problem that involves masses of compounds.

Limiting Reagents Video from Class https://www.youtube.com/watch?v=nZOVR8EMwRU

Same fellow solving a problem with masses https://www.youtube.com/watch?v=N0dTXcoHI-I

For homework this week there are 3 different short assignments.

1. For homework this week do the following questions based on today's lab.  Since both groups got .2 g of CO2 feel free to use that as your mass generated.  I've included  a photo of the answers as well.

2. Answer the limiting reagent questions in the email 

3. Answer the limiting reagent questions in the first worksheet in the enclosed .pdf.  Please feel free to use the other problems as practice.  Answers for this are also included.

Questions based on the lab

1.  Find the percentage composition of carbon in CO2.

2.  Look at your data and, using the percent composition of carbon in CO2 (the answer you found for #1) find the amount of carbon you had in your final mass of CO2 generated.  In other words, multiply your mass of CO2 generated by the percentage of C in CO2.

3.  Find the percentage composition of carbon in Sodium Bicarbonate.

4.  Using the answer you found in #3, find the amount of carbon you started with.  In other words, take your mass of Sodium Bicarbonate and multiply it by the percentage you found in #3.

5.  The answer in #2 is the mass of carbon you ended up with.  The answer to #4 was the amount of carbon you started with and (thanks to the law of conservation of mass) you should have ended up with.   Chances are you lost some carbon along the way and so, with that in mind, you need to find your percentage error.  To do this take the mass you ended up with (answer #2) minus the mass you started with (answer #4) and divide that number by the what you started with (again answer #4).  Multiply that by 100 and that's is your percentage error.

In other words ( (Mass you got - mass you should have gotten)/Mass you should have gotten) x 100 = percentage error.  You want a small number here.  

6.  Why should answer #2 and answer #4 be the same?

Limiting Reagent Questions 

1.  4NH3 + 5O2 —> 4 NO + 6H2O

a.  If you start with 6 moles of NH3 and 9 moles of O2, which is the limiting reagent?

b.  Which is the excess reagent and how much many moles would you have left?

c.  How many moles of NO do you make?

2.  2 Al + 3 Cl2 —> 2AlCl2

a.  If you start with 4.5 moles of Al and 3.2 moles of Cl2 which one is the limiting reagent?

b.  How many moles of excess reagent do you have left?

c.  How many moles of AlCl2 do you get?

3.  2Fe  + 3S —>  Fe2S3

a.  If you start with 2.6 moles of Fe and 1.6 moles of of S which one is the limiting reagent?

b.  How many moles of excess reagent do you have?

c.  How many grams of excess reagent do you have?

d.  How many moles of Fe2S3 do you get?

e.  How many grams of Fe2S3 do you get?

Help for the chem homework this week

Hi folks,

I'm including the steps to these empirical formula problems.  They are the same thing that you should have in your notes but  just in case…. :)

Also, I'm going to indicate which problems each set of steps goes with for the homework worksheet.  Hopefully this will help make these a bit smoother to tackle. 

A. Finding empirical masses if you know masses of elements

1. Divide masses of the elements given in the problem by their molar mass
2. Divide all answers by smallest answer found in #1.
3. Find smallest whole # for all

B. Empirical formulas with percentages  Problem 1,2

1. Assume you have 100 g of the compound so that the percentages can be the same as masses.
2. Divide each percentage by it's molar mass
3. Divide all answers by smallest answer found in #2.
4. Find smallest whole #'s for all atoms in the molecule.

C. Empirical formulas with mass of molecule  Problems 3, 4, 5 (remember percentages can be used like  masses)

1. Divide mass of each element given by the total mass of molecule to find percentage of element in the molecule.
2. Divide those masses by the molar mass of each element.
3. Divide all by smallest answer found in #2
4. Find smallest whole #'s for all

D. Going from Empirical to Molecular from molar mass of molecule  Problems 6, 7, 8

1. Find the molar mass of the empirical formula
2. Divide molar mass given by empirical formula's molar mass.
3. Multiply each atom in the empirical formula)by answer to find Molecular formula

E. Going from empirical formula to molecular formula from masses of elements in compound  Problems 9, 10

1. Find empirical formula of compound (See either A or B)
2. Find Molar Mass of the empirical formula.
3. Divide molar mass given in problem by empirical formula molar mass
4. Multiply the atoms in the empirical formula by answer in step 3 to find molecular formula.

2/15 Chemistry Class and homework due 2/22

Hi folks,

This week we took the time learn how to work with empirical formulas in every way we possibly can.

For homework this week do the questions 1 - 10 on the first page of the worksheet at this link.  Answers are included but he does use a different system than we use in class to solve them.

There are more problems on the sheet if you would like to practice them but they are not assigned. 

If you'd like to read a bit about empirical and molecular formulas I'd highly recommend this page.  It does a quick, nice job of explaining what empirical and molecular formulas are and it's hilarious!  There are also some worked examples there to take a look at.

Recording of 2/15 Chemistry Class

https://youtu.be/Klca9MMez6I

Unfortunately, the last bit of the lecture was not recorded since I turned the camera off when we started that and I didn't turn it on again.

1/8 Chemistry Recording - Percent composition and Empirical formulas

https://youtu.be/OcG2RpMVLeA

1/8 Chemistry update and homework due 1/15

Hi folks,

Today we we covered a couple of quick but important topics in chemistry.  Percent composition and empirical formulas.  Next week we will dive a bit deeper into empirical formulas as well

For homework this week please do the enclosed .pdf.  The answers are enclosed so see if you can really master these before next week.

2/1 Chemistry Class update and homework due 2/8 Take Home Test!!!

Hi folks,

We spent a bit more time reviewing stoichiometry today.  It's tricky stuff but the more you work with it the easier it gets.  We also did a lab today where we put much of the material we've been learning this year to the test in order to measure the width of a molecule using nothing but soap, water and pepper.

For homework this week, do the following take home quiz.  This will be worth the same amount as our classroom quiz so please spend quite a bit of time with it to get a good score.

Good Luck!

2/1 Chemistry Recording - Stoichiometry review

https://youtu.be/ZIQQKX8Hgto

Chemistry Class tomorrow

Hi folks,

I hope folks are doing OK with the stoichiometry stuff we introduced last week.  It's pretty confusing so we will spend some more time tomorrow doing some problems together.  Just to let you know, there will be a quiz tomorrow but it won't include the problems on this week's homework.  However, it will be asking you to convert measurements to moles and moles to measurements (the stuff you did for homework the week before this) so be sure you get that down pat.

Here is a bunch of worksheets with answers for you to practice.  This isn't homework, just extra problems if you want them.

Best,

Jim Mueller

(919) 907-3217

1/25 Chemistry update and homework due Feb 1

Hi folks,

Today we took our wonderful new found skill of using the mole as a tool and began to use it as it was meant to be used, in chemical equations.  

For homework this week, you guessed it,  practice this wonderful new skill.  Please do the enclosed .pdf.  Full explanations of the solutions are included at the bottom.   This author solves the problem using unit conversion which is fine to use if you wish.  Personally, I find the "Unknown over Known" ratio to be easier but whichever works for you is fine.

Good luck folks.  Remember, feel free to rewatch the recording if you'd like to see the walk through again.

Best,

Jim Mueller

(919) 907-3217

1/25 HS Chemistry Recording - Stoichiometry

https://youtu.be/WIGH67QWNjY

1/18 Chemistry Recording - Mole Conversions

https://youtu.be/GuSvsos7kFg

1/18 Chemistry update and homework due 1/25

Hi folks,

Today we spent a lot of time learning how to work with the concept of the mole. We did several conversions from moles, to mass, to liters and to particles and back again. The mole is just amazing! :)

For homework this week I've got another wonderful worksheet filled with endless problems. You can do them while you're watching the eclipse! The answers are included and they are the first page so try no to peek as you scroll down the document. :)

By the way, for number 2, just do a to e. Feel free to do the rest if you wish.

The Worksheet for the homework

I sent all the instructions and forgot to included the worksheet!  

Here you go.

1/12 Chemistry Recording - Review

https://youtu.be/eQ3v-5AWg9w

1/11 Chemistry update and homework due 1/18

Hi folks,

Today we took the time to try to really solidify what we've been working on up to now.  We want to make sure everyone has a pretty firm grasp on how to "read" chemistry.  We also continued to ease in to the concept of the mole.

For homework this week, please do the following questions in the enclosed worksheet.   There are a lot of question but they are very quick.  This is very similar to what we did in class this week but she uses the term OWL instead of Mueller.  So, for this worksheet, assume that an OWL is 6 of anything.

This worksheet's kind of odd so don't hesitate to ask if you have any questions about what to do.

Page 3, do every other question

Page 4, do every other question

Page 6, do every other question

Page 7, do every other question

Page 9, do all the questions

Page 10, do every other question.

Page 12 do all of #3 and #4  (They are asking you to work with real molar mass here.)

Last but not least, please do the following conversions.  This is going to be very typical to the type of math you are going to be doing with moles.  I've included the answers below so you can check yourself.

Notice on the following problems that you are converting mass to Mueller's/OWLS and then using that result to convert Mueller's/OWLS to numbers of pieces.

1. If you had 400 g of Hot Wheels Cars, how many would you have?

2. If you had 45g of pennies, how many would you have?

3. If you had 5g of foam balls, how many would you have?

Notice on the following problems that you are converting numbers of pieces to Mueller's/OWLS and then using that result to convert Mueller's/OWLS to mass.

4. If you had 600 Popsicle sticks, what mass would you have?

5.  If you had 3600 poker chips, what mass would you have?

Here are the Mueller Masses we found in class.  Use these for the Mueller/OWL mass questions.

Popsicle Sticks 8.5g

Pennies             15g

Poker Chips       42g

Hot Wheels Car 200g

Foam Balls         10g

Answers for the questions in the email. 

1.  400g/200g = 2 muellers of cars.   2 x 6 = 12 cars

2.  45/15 = 3 muellers of pennies.  3 x 6 = 18 pennies.

3.  5/10 = .5 muellers of foam balls.  .5 x 6 = 3 foam balls

4.  600/6 = 100 muellers of popsicle stick.  100 x 8.5 = 850g

5.  3600/6 = 600 muellers of poker chips.  600 x 42 = 25,200g.