May 11, 2006

The last of the final grades were entered this morning.  The grading was done on a 90/80/70/60 grading scale without a curve.  I looked at borderline cases, but "borderline" means within 1% of the cutoff.

I hope everyone has a safe and happy summer. This semester was a lot of fun for me, and I hope you enjoyed it too.

May 10, 2006

Final grades are in!  Well, almost... 16 out of 20 classes have been submitted, and the rest will be posted Thursday morning.  You can check your grade online by going to UT Direct and clicking on Academics, and it's the first link under there.  Please look there and do not e-mail me -- I can't send out 337 individual e-mails about grades!

May 9, 2006

Final grades are still not determined. I am still waiting on grades from some TA's.  Patience, Grasshopper.

Some grades are known, but the borderline grades are not.  I will post a message here when all the grades have been worked out.

April 26, 2006

Final grades are not determined yet.  The last lab reports won't be turned in until Wednesday, May 2, and then the TA's have to grade them. I won't know what final grades are until the following week.

Now that the labs are finished, I will not be holding my regular office hours.  E-mail me if you want to talk.  I won't be in on May 1 until after 4:pm, but I will have access to e-mail for most of the day.

April 23, 2006

MAKE-UP WEEK!  If you missed a lab and haven't already made it up, now's the time.  Come at the same bat-time to your same bat-lab. We'll probably move you to another lab, though, since we're consolidating students into fewer labs order to save Ethan and the TA's a lot of work.  Monday afternoon we will be working in rooms 4.116 and 4.124, and Monday evening we will be in rooms 4.124 and 4.140.  We'll have signs up and we'll be there to make sure everybody gets going okay.  Also, check out of your drawer this week if you haven't already!  If you don't, the stockroom staff will check you out and bill you $15 for their services!

No lecture this week, and no quiz. Oh, stop crying, you're a grown-up.

Easter Sunday, 2006

This is it, folks -- the final week of lecture.  I know this is a cause of great rejoicing  among the masses, but I'm kinda bummed about it because I've really enjoyed this semester.  Still, it's been a long run for all of us, and fun or not, it's about time we wrapped it up.  Please make an extra effort to get to class on time this week for the course evaluations in lecture.  We'll also do TA evaluations at the start of lab this week.

The slides and note pages for Experiment 10 are online.   The Kinetics Discovery Lab is the consensus favorite among CH204 students every semester -- it's more fun than a redox titration, shorter than Thermochemistry, and doesn't smell as bad as all those acid-sulfide mixtures you made in the Qualitative Analysis lab. (And all this time you thought that was the person working next to you...!)

Don't forget the extra credit homework  is due at the start of lab this week!

April 12, 2006

The extra credit homework that was passed out in lecture this week is now online. It's due at the start of lab next week, and no late homeworks will be accepted. This is to be done INDIVIDUALLY!  No group work, no asking friends for answers.   It's all honor system, so use this opportunity to prove to yourself that you're honest enough not to cheat for the sake of ten lousy points in a chemistry class.

Also -- if you got a 5 on your unknown summary sheet for Experiment 4 (Acid-Base lab) and have not submitted a regrade or already talked to me about it, e-mail me right away.  There are probably a lot of points waiting for you, lost to a minor calculational error. Not everyone gets more points from a closer look at those numbers, but the vast majority do.

April 9, 2006

Lecture notes and slides for Experiment 9 are now online.

Also, Dr. Leytner has provided yet another cheat sheet to help you through this week's calculations.  It covers the calculations for parts 3 and 4 of Experiment 9.  You can find it on the Freebies page.

April 2, 2006

The lecture notes for Experiment 8 are now up on the Power Points page. Bring a watch to lab this week if you've got one -- you'll be timeing your temperature readings every 15 seconds, and the lab clocks aren't always convenient (or operable).

March 29, 2006

Experiment 7   Okay, listen up.  Everybody is asking me how they're supposed to know how many moles of K+ there are per gram of sample.  You guys should be able to figure this out -- don't e-mail me before you even think about it!  Flex those brain muscles a bit and you'll see the answer staring you in the face. Yes, the answer really is what you think it is.

Also Experiment 7:  In Question 8 you are supposed to write a balanced equation using the chemical formula for the crystals that you came up with based on your data.  But if your data isn't as good as it might be, you'll probably end up with an incorrect formula (particularly for the waters of hydration), and the equation for the reaction will never balance.  Presumably you all know what the correct chemical formula for the crystal is supposed to be -- and if you don't already know it, you at least know where to go to find out -- so if your formula is not correct, balance the equation in Question 8 using the correct formula instead.

The Cheat Sheet for Experiment 7, courtesy of Dr. Leytner, is now online on the Freebies page. I handed this out in class before we did the second half of the experiment. Remember that Experiment 7 also has an Unknown Summary Sheet that includes your results for oxalate from Experiment 6 and as well as your results for iron from Experiment 7.

March 25, 2006

This week we'll make and measure our standards for Experiment 7, which will enable us to determine the concentration of our sample.  The lecture slides and notes for this week's lecture are available on the Power Points page.

March 19, 2006

If you were waiting for the last minute for me to post the lecture slides for this week, you're in luck, because that's when I posted them!  They are now online, along with lecture notes pages, both in PDF format.  Spring break ended way too early this year...

This week in lab we are doing Experiment 7 parts 1 and 4.  You won't turn in a report and discussion until we complete the entire experiment, but when we return to finish the experiment, you will have to turn in the post-lab as though it were the pre-lab for next week's experiment.

March 18, 2006

Take a look at Experiment 7, Part 4, Step 3 on page 54 of the lab manual.  There is a calculation buried in the procedure.  This calculation is required in your report for Experiment 7.  Some students miss this and lose points for it.  I will remind you in class and again here before the report is due, but you can spare yourself some potential grief if you make a note of it now so you don't forget when you're doing the report.

March 10, 2006

If you e-mail me during spring break, be patient waiting for a response.  I have a full schedule all week long and won't be checking e-mail as often as usual.

When we return from spring break we will begin Experiment 7.  We will do Parts 1 and 4 the first week, and Parts 2 and 3 the following week.  (In Parts 1 and 4 you prepare and measure your sample, and in Parts 2 and 3 you prepare standard solutions and measure them.)

In Post-Lab 6 Question 2 you may find it easier to balance the equation if you use a net ionic equation instead of the overall chemical equation given.  Take out all the ammoniums and chlorides and balance the two half-reactions involving iron and sulfur.  When you have a final redox equation, add the ammonoiums and chlorides back in to get the final equation.

In Post-Lab 6 Question 4, 23.0 mM means 23.0 milliMolar.   If you find this conflusing, just divide by 1000 to get units of Molarity, and continue on from there.

In Post-Lab 6 Question 5, don't let the BaI2 fool you -- that's not I2 in that compound, it's two moles of I- for every mole of BaI2.

March 5, 2006

The Power Point slides are now up for Experiment 6, along with the note pages for that lecture.

February 26, 2006

February 19, 2006

The Power Point slides are now up for Experiment 4, along with the note pages for that lecture.

February 17, 2006

Experiment 3 help   I'm getting a lot of questions from people who don't understand what the Discussion and Post-Lab questions are asking for in Experiment 3, so maybe this will help:

The first Discussion question says to write balanced chemical reactions and net ionic equations for the reactions that gave you a result (in this case, a precipitate).  There were 11 reactions in Experiment that resulted in precipitates.  You may have seen something that looked kinda sorta like a precipitate in some cases, because some of the products in other reactions are slightly soluble, and at the concentrations we were working at, they formed only a trace of actual solid.  You should have 11 reactions that are insoluble according to the solubility table in the back of the lab manual.  So, for example, the reaction of silver nitrate and hydrochloric acid would look like this:   

                   AgNO3 (aq) + HCl (aq) → AgCl (s) + HNO3 (aq)

and the net ionic equation would be

                         Ag+ (aq) + Cl- (aq) → AgCl (s)

It's your job to determine what the other ten precipitates are, and write the balanced chemical equation and the net ionic equation for each of the reactions.

Post-Lab question 1 gives you two chemicals -- they are both soluble in water -- and asks you what test you could perform to distinguish between them.  Imagine that you have two beakers in front of you, each one containing a clear liquid.  How could you determine which one is which?  In the first set, you are given AgClO3 (aq) and Na2CO3(aq).  You need to come up with a reagent that you could add to both beakers that will form a precipitate in one of them, but not in the other.  Look at the solubility table in the back of the lab manual for guidance (and here's an extra hint -- look at the equations above!). The last set of solutions in problem 1 is a soluble salt that you will not be able to precipitate in any way, and water, so you'll have to come up with some kind of test other than precipitation to be able to tell these two apart.  (Hint:  our last two labs provide two perfectly good answers to this question.)

February 16, 2006

Three things:

1)  Your unknown number for Experiment 3 is just your lab drawer number.

2)  Take a look at Experiment 4 if you haven't already.  The Pre-Lab questions require a lot more work than they have up till now, and the preliminary write-up will also take more time and thought than previous preliminary write-ups have.

3)  The weather is warming up, and more of you are going to want to wear shorts during the day.  If you're going to wear shorts on lab day, remember to throw a pair of sweat pants into your backpack for lab.

February 12, 2006

<rant>
Look, guys -- when I said to notify me as early as possible if you are going to miss a lab, I didn't mean you should e-mail me on Sunday afternoon of the week you're going to miss.  I meant tell me NOW.   There are over 50 make-up labs already scheduled for this class.  Spaces fill on a first-come, first-served basis.  Check your schedule, and if you have a conflict, let me know NOW.  The longer you wait to notify me of conflicts, the less sympathetic you will find me when you need to schedule a make-up lab and can't get one.
</rant>

The Power Point slides for Lecture 3, along with the note pages for that lecture, are now online.

February 5, 2006

Lotsa good stuff added to the site today.
    -- I have had numerous requests (one is a number, isn't it?), to provide lecture note handout pages in addition to the regular Power Point slides.   Each page of the lecture notes has three miniature copies of the lecture slides, along with a space on the side for taking notes.  (Somebody takes notes in my lectures?  I gotta start watching what I say!). I'll post my Power Point lectures in two formats from now on, the mini lecture notes for the compulsive note-takers among you, and the full-size slides for those who insist on re-living the original 204 lecture experience in the comfort of your own hovel.
    -- One of the discussion questions in Experiment 1 asks about comparing the accuracies of the three types of volumetric glassware we used.  Our experiment really doesn't provide that kind of comparison information, but that doesn't mean you have to wallow in ignorance for the rest of your lives -- or even the rest of the semester!  I've added a short PDF file to the Freebies page that compares the accuracy of the glassware we used.  This is not required for the post-lab question, but if you're going to do further lab work in chemistry or biology, it's good to know.
    -- Also on the Freebies page is a discussion of determining the error in the slope of a line.  You may have noticed that in Experiment 1 we talked forever about determining experimental error in part 1, and then we ignored it completely in part 2.  How many digits should we have used when reporting the density in part 2?  What was the magnitude of our experimental error in part 2?  Our colleagues in Jamaica have a short web page that describes how to determine the error in the slope of a line using what's known as the box method, and it even includes the Excel function for calculating the error in a slope.  It's definitely worth taking a look at.
    -- Unknown Summary Sheets are now available online.  You'll need one for each of the next three experiments.  We'll talk more about them in class.
    -- Yeah, the Super Bowl was a pretty dull game this year, but at least the Steelers won, and that counts for something, especially since the commercials were so LAME-O.  The Whopperettes?  You've got to be kidding.  Because of that one pathetic commercial, I refuse to eat at Burger King until after next year's Super Bowl, and maybe not even then.

February 4, 2006

Please, pleasepleaseplease, when you e-mail me, include your section number and TA's name in your e-mail.  Please?  Thanks.

February 1, 2006

      We've survived the first lab experience!  Outstanding!  And we broke a lot less glassware this time around, too.  Don't wait too long to start on the report.  Experiment 2 is a lot more involved than the Coke lab was, and will take longer to prepare for.
      Rumors say the Co-op now has notebooks in stock, so hie thee down to the drag and get one before they run out again.  Some of you don't have combination locks yet -- shame, shame, shame.  They're only five bucks, and you can get one lotsa places.  Make sure you have one next week or you'll start losing technique points for not being prepared.  'kay?  'kay.

January 29, 2006

Jamaica!  No Problem!
    We will be talking about experimental error this week in lecture, and there's a very good web page that explains the use of standard deviation as a measure of error in chemistry labs.  This is from the University of the West Indies in Jamaica (field trip!).  Their discussion is particular to the measurement of acetic acid content in vinegar (one of the experiments in their general chem lab), but their use of standard deviation for experimental error applies directly to our work in Experiment 1.  Give it a look, mon.  The first half or so of the page is most applicable, but the whole page is very good.  Also, this week's Power Point presentation is now available for download as a pdf.

January 25, 2006

1)       I have added a point breakdown table and a sample quiz to the Freebies page. The point breakdown tells you how many points each lab is worth, and how the points are distributed. You can use this to keep track of your grade throughout the semester if you are so inclined.  The sample quiz is one of the quizzes I gave last semester, but since I'm showing it to you now, you know it's NOT what you're going to get this year.  But hopefully it'll give you a general idea of what to expect.

 2)     Also on the Freebies page is the sample Preliminary Lab Write-Up and Sample Report that I showed in class.  These are for Experiment 1, so if you simply copy the Preliminary Lab Write-Up into your lab notebook, you oughta be good to go for next week.

January 21, 2006
     Chem 204 you are cleared for takeoff!  This is gonna be a fun class. It's a lot of work for two measly credits, but it's tons o' fun and you'll also learn some actual useful science along the way.  I'm looking forward to this semester, and I hope you are too.  See you in class.