Sept 28: Test Day

Today you took your test!  Homework is to do this tutorial on precipitation reactions.  Take notes (with pictures!!) and submit your tutorial results to my e-mail: marguerite dot wiseman at apsva.us (but put a . in for dot and an @ for at)

 

Reaction Videos here show some examples of precipitation reactions.

Sept 27: Review Day

Today I handed out a challenge stoichiometry problem that involved 3 sequential reactions…after going over how to do that you all

continued to work on the packet problems including the textbook problems.

So for tomorrow you must have the following complete:

  • All of page 1
  • 75% of page 4
  • 75% of page 5
  • All of page 7 OR all of page 8
  • All of page 9 and 10
  • All of page 11
  • All of page 12
  • At least 4 limiting reactant problems (page 13-16 )

 

What will be on your test…

Solutions and stoichiometry…see objectives.

Sept 26: Solutions Review

Agenda

1. Review solutions
2. Make your 0.5 M (or whatever most concentrated solution)
3. Set-up lab notebook w/ appropriate data tables
a) Data for making each level of IV
b) Data you will take for each reaction
c) Results (i.e. actual yield, theoretical yield,              percent yield)
4. Calculate theoretical yields for each level of the IV
5. Watch vacuum filtration video

Some Review Questions

1. Write a dissociation reaction for Aluminum chlorate
2. A solution contains 3.0 moles of Aluminum chlorate.  How many dissloved particles are in the solution?
3. Which contains the most solute?
a) 10.0 mL of 3.0 M Sodium chloride
b) 100.0 mL of 0.30 M Sodium chloride
c) 200.0 mL of 1.0 M sodium chloride
4. Which of the following is the most concentrated?
a) 10.0 mL of 3.0 M Sodium chloride
b) 100.0 mL of 0.30 M Sodium chloride
c) 200.0 mL of 1.0 M sodium chloride
5. If 10.0 grams of sodium chloride is added to 200.0 mL of a 3.0 M solution of magnesium chloride, what is the concentration of ions in the final solution?
6. What is an electrolyte?
7. How do covalent molecules behave differently from ionic compounds when dissolved in water?

8. What is the difference between ions that are aqueous and ions that are in a precipitate? Draw a picture.

Homework: Finish today’s agenda, study for test

Sept 24: Percent yield

Agenda:

  1. Pop quiz on limiting reactant and dilutions?
    1. Tutorial: Dilutions, Submit completion to me via e-mail: marguerite dot wiseman @ apsva.us
    2. Tutorial: Limiting Reactant, Submit completion to me via e-mail: marguerite dot wiseman @ apsva.us
  2. Comments on labs
    1. Uncertainty on balance
    2. Use of uncertainties for calculated values
    3. “Commenting on results” what it means and using data, calculate percent error
  3. Percent Yield Notes and Practice 
  4. Design a lab to test the effect of concentration on percent yield of a reaction
    1. Directions for completing group procedures and the rest of the lab
    2. Hypothesis Google Form:

Sept 21: Limiting Reactant Problems

Today I handed back the test and let you know that retakes for naming and formulas would be on Wednesday during 8:20 or H block. If you intend to retake you need to come to a review session on Monday after school or you need to provide some evidence that you are actually going to do better this time around.

Help for naming here or do this tutorial

Help for empirical formula here, do practice from textbook.  Answers for exercises (tan boxes) are in the back of the book), do more of the virtual lab problems, do hydrate worksheet

I then starting lecturing, old school style.  I went over the mole map, basic stoichiometry and limiting reactant.  There’s videos for all of this, but you could also try reading your book!

Finding excess reactant:

Sept 20: Weird short day/work day

Today you had time to finish up your Mole ratios lab, work on naming acids, review solutions calculations (packet) and begin reviewing stoichiometry (packet).

Sept 19: Conservation of Mass and Mole Ratios Lab

Today we did a little smart board lesson on conservation of mass and the idea of mole ratios. You guys were supposed to balance reactions and draw pictures at the molecular level so that I could see that you understood what the coefficents meant, etc.  Then we completed the mole ratios lab.

 

Homework was to continue with the packet: page 3, 4, 5. Use you book to learn patterns for naming acids and practice naming (page 3, I think), on page 5 you should practice balancing combustion reactions. These are often the most challenging.  Here is a video if you need help!

Sept 18: Solutions

Today we started with notes on the smart board (here’s a pdf copy).  We went over dissociation of ionic compounds and you did a piece of this activity.

Homework is to do page 1 in giant worksheet packet (although doing page 4 would also be good since we did enough in class for you to do that page as well).

If you need help with Dilutions – use your book (end of chapter 4) or watch video below:

If you need help with molarity:

Sept 12: What’s on the test, lab, practice quiz, etc.

Today we started with a practice naming quiz. When I went over the answers I also reviewed some naming rules and patterns

Next we prepared for lab – set up lab notebook, did pre-lab problems, etc.  We only had about 40 minutes to do the lab and there was so much difficulty in getting equipment found, set-up, etc. that only one group actually managed to get a melting point!  So we’ll try again tomorrow!

In the mean time, here are some more details on what is on your test on Monday

  • no safety questions,
  • No uncertainties
  • Sig figs and dimesional analysis only as they apply to mole calculation problems
  • No lewis structures
  • No organic functional group identification
  • Ions will be limited to the ones you can predict from the periodic table, transition metals and the BOLDED ones on this ion sheet.

I like all the topics we are studying to fit together in a nice neat package…here is the story for this unit.  You could use this as a study guide, even.

  1. How do we know that there are atoms? What evidence did Dalton have?
    1. Law of Definite Proportions
    2. Law of conservation of mass
  2. Part of Dalton’s hypothesis was that atoms combine in whole number ratios.  We can experimentally determine the percent by mass, but in order to determine whole number ratios we need….good atomic weights and the mole concept
  3. In order to get good atomic weights we needed to take into consideration the different “flavors” that atoms come in.  Various isotopes have different masses so we utilize a weighted average since we don’t just deal with one atom a time (usually).To get average atomic weights we use mass spectrometry (Dalton didn’t have this –  I don’t know how they did it!)
    1. Outline how Mass Spectrometry works –
    2. Determine relative abundance of various isotopes and calculate average atomic weight based on spectra
  4. The mole concept was developed because we generally are unable to measure just one atom at a time.  The mole was defined such that the mass on the periodic table, not only represented one atom, but also represented the mass in grams of a large collection of atoms.  It just so happens that the number of atoms in this collection is …
  5. Now that we have a way of counting atoms by weighing we can determine the whole number ratios in which they combine
    1. Empirical Formula  Problem
    2. Hydrates
  6. It turns out that some elements combine in the same proportion, but have different properties: glucose and fructose.  Thus, it is necessary to know not just ratios, but the actual number of atoms in the molecule.  For this we need the mass spectrometer again.
    1. The molecular ion peak on the spectra gives …
    2. Molecular formula problem
  7. Now we have a way of keeping track of the atoms in each molecule we needed to develop a systematic way of naming them.
    1. Nomenclature
  8. Knowing the molecular formula also allows us to understand many of the other chemical and physical properties these molecules have.  Many of these properties result from the ratio of one element to another.
    1. Mole ratio problems (How many atoms in 10.o grams of copper (II) carbonate?)

Sept 11: Work on Empricial formula virtual lab

Today we spent the short class completing the empirical formula virtual lab you started last class.

I also handed out the lab for next class (Analysis of Alum) and a worksheet to help you with vocab on hydrates.

Homework: Finish virtual empirical formula lab, read alum lab, you may also need to read the page in the textbook on hydrates.  If you have extra time – memorize those ions!!