No school. Grading day.
Went over old redox test to review terms and concepts.
Build a battery lab. Groups of two built certain combinations of half cells and then everyone recorded the voltage of each cell. You drew your half cell and then after doing the first part of CA 50 and watching this video you added some details: half reactions, direction of electron flow, anode and cathode labels, and direction of ions in salt bridge. Then we looked at the chart of standard reduction potentials in your textbook and talked about what they mean. I introduced the idea of the standard hydrogen electrode and explained where the voltages came from. HW is to finish CA 50/ read chapter 19/ do textbook problems (unit outline)
Today we started with a practice AP problem from your packet. This led to a discussion of the effect of concentration on cell potential. If the concentration at the cathode is decreased this gets you closer to equilibrium so the cell potential goes down. You can also use Le Chatelier’s principle if you think about the reactant concentration decreasing, this suggest the reaction shifts in the reverse direction which would lower the cell potential (not as much driving force for the forward reaction). If you decrease the concentration at the anode, though, the cell potential will go up. This is like removing product which would cause the rxn to shift towards the products, increasing the driving force for the forward reaction.
Next we learned how to use the cell potential to calculate the equilibrium constant. I introduced the delta G = -n F E and reminded you of delta G = -RTln K. Just remember when determining n, the moles of electrons transferred in the reaction, you must have a balanced reaction. E.g. their are 6 moles of electrons transferred in the reaction between Al and Fe2+
(2Al + 3Fe2+ –> 3Fe + 2Al3+)
Next we looked at how to calculate the cell potential under non-standard conditions using the Nernst equation. We did 19.85 to practice.
During the 2nd half of class we talked about electrolysis and practiced predicting products for molten and aqueous solutions (see power point near the end)
HW: Textbook problems. Study for electrochem test on Monday
Today we worked textbook problems from chapter 18 all class to review all that we had learned regarding work, entropy, heat of reaction, gibbs free energy. We did 18.31 to 18.55.
We will work on delta G and equilibrium
We will review
Lecture on exo/end, system vs. surroundings, calorimetry (including phase diagrams) using Thermodynamics part 1. Second half of class we did bond enthalpy and hess’s law.
We started with heats of formation problems form Thermodynamics notes part 1. Then I went over work and internal energy at the beginning of Thermodynamics part 2.
Physics fair. No class.
Today we reviewed thermodynamics problems from Thermo part 1.
Today we started with Gibb’s Free Energy/ Entropy power point. Made it all the way up to delta G and K.
Do not remember this week either.
I do not remember what we did this week…
Today we started by reviewing the 5 basic electron geometries and then I lectured on hybridization. We spent the first half of class working through Molecular Modeling for you to practice figuring out hybridization. Then we used the modeling kits to build structures that showed pi bonds.
HW: Finish molecular modeling lab except for L and M
Today we started with organic naming practice and learned two new functional groups: aldehydes and ketones. Then we talked about the difference between polar bonds and polar molecules and identified the factors that determine if a molecule will be polar or non-polar. The gist is that if a molecule has lone pairs and has polar bonds it will be polar (unless it is one of those linear shapes that has lone pairs, but bonds are arranged in such away that dipole moments cancel out). If it just has lone pairs but no polar bonds it might be slightly polar or non-polar. We would look at the properties to say for sure. Today’s notes.
HW: Finish molecular modeling lab practice. Here’s the answers.
Today we started by building benzene and learning about pi bonding networks that result in delocalized electrons which gives the molecule more stability. This happens in all molecules that have resonance structures. Next we went over the naming rules for carboxylic acids and learned to identify various functional groups including ethers, etsters, amines and amides. The second block you worked on the organic modeling lab.
HW: Finish organic modeling lab (answers)
Today we started w/ pg 13 in the packet to practice determining if a molecule is polar. Here’s my answer key – but I have to make an amendment to the questions about ions. In general, we would never say an ion is polar or non-polar. An ion has a charge, therefore it cannot be non-polar (no charges) and it cannot be polar (has BOTH a positive and a negative side). However, we can look at the structure and see why it has the overall charge that it does. NH4+ for example, does not have the polar bonds cancel out b/c all the arrows are pointing towards the center. This means all the electrons in the N-H bonds are located more towards the center of the tetrahedron, leaving the outside positve. Hence, NH4+ is a positive ion. SF5- has all the polar bonds point out. The planar dipoles cancel out, but the polar bond on top does not so one would expect this ion to have be more negative on the side with the non-planar F atom. The positive charge that would be on the S is likely blocked by the presence of a lone pair.
HW: contemplate resonance and its relationship to the pi bonding network
First I had you look for patterns in acid strength trends. 2nd half you reviewed by finishing labs and working on practice tests.
HW: study for test
Review for ionic bonding test.
Ionic bonding Test (unit 9a)
I was out so you worked on reviewing stuff from last year in a google classroom assignment.
Today we started by learning organic naming. And then in the last 15 minutes we went over resonance and calculating formal charge to determine the best Lewis structure. Here’s the notes. If you missed the organic lecture or need to see it explained again – here are some of the videos I made at my old school.
- What are all the possible shapes?
- What are the bond angles for each of the shapes?
- How many bonds/ lone pairs make up each shape
- What is the difference between electron geometry and molecular geometry?
- How are double and triple bonds treated when determining shape?
- Using the real molecules sim
- Look at the structure, determine the shape, see if you are correct
- Look at the bond angles. Do bond angles for real molecules match theoretical bond angles?
After you worked on the simulation we summarized and got out the modeling kits to go over the different shapes and their arrangements. Here’s the notes. For the last 15 minutes we worked on the molecular modeling lab.
HW: Draw Lewis Structures and determine shapes for all of set 1 and set 2 of molecular modeling lab on page 15.
No school b/c President’s day
You all took your atomic structure test.
Intro to bonding notes, ions formed by transition metals, ionic radii, ionic bond strength. Here’s the notes.
HW: review what we learned today. Start google classroom questions.
Trends in ionic and metallic melting points + Born-Haber cycle notes. We watched a video on formation of sodium chloride to show the energy given off in this reaction. That brought up some questions about sodium in its natural state so we watched a bit of this video. Here’s the notes for today.
HW: Work on google classroom questions, do #1,23 on page 15 in packet, read 10-12 to learn about alloys.
Today we reviewed born-haber cycles by having your work in groups making posters for the last few problems on page 15-16. The second half of class I lectured a bit on coordinate covalent compounds, you practiced naming, identifying ligands, coordination numbers and charges on the metal ion. No naming will be on your test – just the vocab: ligand, coordination number and interpreting the charge of the metal ions. Next we talked about why transition metals are colored in solution and then n the last 15 minutes we did a lab using complex ions to distinguish Iron (II) from Iron (III). Nothing to write down – was just an exploration lab (so don’t worry if you were absent).
HW: Review. Test is on TUESDAY!
Today we started with review of atomic structure (first few pages of packet) and then worked on Coulomb’s Law ChemActivity. During the 2nd half we reviewed periodic trends including interpreting graphs and using pattern in IE to predict group or valence electrons of a given element.
Today we reviewed with a couple of practice AP problems from the packet and then finished the PES packet. Most of you had to finish some of the PES for homework.
Today we started with review of a couple more AP problems on page 43 (2005 and 2008) then I checked page 21 while you guys worked on pg 22. That launched us into the lecture on electron configurations and orbital diagrams because the PES is evidence that the Bohr model needs refinement. Here’s the notes. We went over all the theory today and did some practice. Tomorrow will perhaps have a little time for battleship and the exceptions.
Practice econfigs and orbital diagrams. Battleship + exceptions: pge 30 and 33 in packet
e-config vocab, multiple choice practice + other review for test on Wed.