Monday: Review for the stoichiometry test tomorrow. We started with homework problems and it became apparent that most of you had not done much limiting reactant work so we started going over the first problem on the limiting reactant section. This was helpful because some of you were thinking of this in terms of atoms rather than molecules…you must use mole ratio, can’t just total up all the atoms of each type and then figure out the limiting reactant since reactions won’t always occur like that. I also showed 3 different ways for figuring out excess and then asked you guys to write down your preferred method. The rest of class we worked more LR problems. In the last few minutes we did a combustion analysis problem just to refresh your memory.
Tuesday: Test on stoichiometry.
Homework: Dilution and molarity videos. The first two listed are the ones I think you need to watch even though you’ve seen 2.b.1.5. The next 3 are only if you truly don’t remember molarity at all or have difficulty calculating the number of ions from the moles of an ionic compound (like how many moles of nitrate ions in 54.0 g of Cu(NO3)2?)
Watch these three only if you need them!
- 2.b.1.1 Intro to Solutions (From first year chem – if you want to review vocab like solute and solvent. Molarity is introduced near the end.)
- 2.b.1.2 Molarity (from first year chem, just shows the math for various problems, but doesn’t explain what molarity is)
- 2.b.1.3 Moles of ions (This is not about molarity, but is about using subscripts to determine moles of ions something you will need to do molarity of ions)
Today we reviewed the process of dissolving for both ionic and covalent compounds and I gave the definition of electrolyte. We worked on 4.20 in the textbook which unlike last year was not confusing at all…no one had any questions really. So the rest of class we worked on various molarity and dilution problems including showing how to solve various problems. Notes from last year (which have a bit more detail as I had to review a number of concepts that we didn’t have to review this year) are here. Notes from this year are here.
- basic molarity (but see chem 1 videos for more if you need it)
- molarity w/ multiple solutions
- molarity mixing two solutions
- dealing w/ mass percent.
Homework: textbook problems and packet (page 1 on molarity of ions, page 2 on molarity w/ multiple solutions and dilutions)
Thursday: We started by learning to prepare solutions using volumetric flasks and then you prepared calcium chloride and sodium oxalate solutions in preparation for lab tomorrow. The rest of class you spent reviewing naming acids rules and practicing.
Friday: Today we started by predicting double displacement reactions including two special types: neutralization and acids with carbonates. We went over complete ionic, net ionic, spectator ions and and drawing pictures. Here’s the notes. Second half of class you completed the chemical formulas lab (will need to be logged in to APS google to open).