Monthly Archives: April 2017

Lab 20G – Day 2

  1.  Calculate the molarity of oxalic acid dihydrate you made in Part 1.  Show your work!
  2. Calculate the molarity of NaOH you standardized in Part 2.  Show your work!
  3. For Part 3, choose one of the unknowns (A, B, or C).  Measure about 0.40g of the solid.  After the titration, calculate the molar mass of the unknown acid.
  4. For Part 4, choose one of the unknowns (A, B, or C).  Measure the pH of the solution (this is the pH of the acid at equilibrium).  After the titration and using a RICE table, calculate the Ka of the unknown acid.
  5. If you are behind in doing the lab, you can come on Goal Day to complete the parts you missed.


  1.  Any Q’s?  You have tutorial time today and next class.
  2. Reminder:  check “AP Chemistry Resources” section on the blog for other resources you may find useful (or not!)
  3. Reminder:  Hand in F/T forms if you are writing the Chem13 News contest asap.
  4. TNT Club is having tutorial sessions this week at lunch in Rm111.  Today’s session is:  ChemCrashcourse#1

Lab 20G

  1.  Prelab check!
  2. Do:  Lab 20G Parts 1 and 2.  Calculate the molarity of NaOH.
  3. Reminder:  Goal Day on May 1.  You can complete assignments, correct assignments, write tests, rewrite tests you have an “I” standing for.  My hours are:  8:30-11:30am, 1-2pm.  You can also complete Lab 20G if you missed one of the lab days.

Lewis Dot Structures

  1.  A funny excerpt about the Periodic Table from one of our Vikings Read novels this year called “What If?”:  What If Exerpt
  2. I will be able to write/draw Lewis Dot structures.  See block 5 notes here:  How to Draw Lewis Dot Structures – block 5 notes
  3. Do:  Electron Dot Structures Worksheet.  See copy here:  Electron Dot Structures Worksheet
  4. Finish Lab 11A Conclusions and Synthesis Questions and hand in today.
  5. Quiz next class on Periodic Trends

Indicators and Practical Aspects of Titrations

  1.  I will be able to select the best indicator for a titration.
  2. Read section 17 and do #108-120 (choose 2-3 questions)
  3. Practical aspects of titrations.  Read section 18 and do #125-130.  You will be using a primary standard to standardize a NaOH solution in your next lab.
  4. Prelab Lab 20G:  Make a flow chart/summary of the procedures.  You will not be using lab manuals and will only have your prelab for instructions.  See copy of lab here:  lab 20G
  5. Note:  we will downsize the lab.  In part 1, make 100.0mL of oxalic acid using the 100.0mL volumetric flask.  In parts 2-4, use a 10.00mL pipette instead of a 25.00mL pipette.  Omit part 5.

Multiple Choice practice tests

  1.  See the college board website released multiple choice sections:

They have released 1999 and 1994 as sample tests.  These are no longer the format for the test (since about 2013).  There are currently more question clusters and diagrams to interpret in the multiple choice section.

2.  2012 practice exam:

3.  a modified 2014 exam:

4.  a modified 2015 exam: