Advanced Placement National Conference – Day 2  (July 23, 2011)

Session Title:  Results from the 2011 AP Chemistry Exam Administration

Session Presenter:  Larry Funck – Chief Reader for the AP Chem Exam

Presenters Website:  Email larry.funck@wheaton.edu for a copy of the powerpoint

Session Rating:  B-

Session Thoughts:  Session was a little slow at the beginning but picked up when he diagnosed the common problems students made on each of the Free Response problems (that and a pretty good joke when he showed a logarithmic graph of the exponential growth of students taking the AP Chem exam – pretty funny for the geeks in the room).

Session Review:  Dr. Larry Funck initially began his presentation by explaining the way the exam was developed and then the way the exam is graded by AP reviewers.  This initial material was pretty much useless and not of great importance for how teachers will instruct their classes.  He could have saved the time here and had much greater discussion on the test itself (which was incidentally what he got the most questions and engagement in the room from).

The great part of this presentation were the misconceptions and common problems he saw students making on the exam.  He also gave some recommendations (although I wish he did more recommendations) on how to teach these concepts differently.  So I’ll diagram what he presented as major problems students made on the 2011 AP Chemistry Exam.

Question 1 – only 1 out of every 6 students gained credit on the buffer section.  What did this show?  Students are not learning or grasping what a buffer is – at all.  This set up my presentation (which would follow his in just a few hours) on how to teach this topic to mastery.  He presented his way of teaching buffers – through a presentation of strong, weak, and pathetic acid-base pairs – not bad but I think it probably engages him more than his students at Wheaton.  He also showed how students must understand conceptually what is going on in each section of the pH graph of a buffer.

Question 2 – On this laboratory problem the most common problem was simple algebra.  A plethora of students thought that one had to dilute a solution by putting 133 mL of the concentration solution to make a 50 mL diluted solution.  That just does not work.  Students also did not understand the safety procedure of not adding water to acids for thermodynamic reasons, how to clean up acid spills practically, and ultimately a working knowledge of dilutions and heating a substance to a constant mass.  There is a lack of inquiry here that most students are not getting in class.

Question 3 – This thermo/electrochem problem showed a lack of depth of students knowledge of electro chem and Faraday’s Law.

Question 4 – The reaction problems and questions exhibited a student’s problems with writing net-ionic reactions rather than molecular reactions.  Dr. Funck did not say so, but I believe that the way students are presented with chemical reactions in Chem I (or Chem Honors) builds in misconceptions that all reactions are molecular rather than go in-depth on what is actually going on in the reaction.  The presenter also showed students had difficulties with ratio, Lewis theory, and simple charges of ions.

Question 5 – This problem initially showed students do not know how to truly draw Lewis Dot Diagrams.  An absolutely huge problem that students have also came from this problem that is important for every teacher to evaluate how they are teaching this concept – as well as the biology teachers before them.  It has to do with a failure to understand that when you vaporize (or boil) a substance, you are not breaking the bonds within the substance but the attraction or intermolecular forces between the molecules of that substance.  Also, there is a failure to understand that when bonds are broken, energy is absorbed.

Dr. Funck detailed the latter part of the problem and his belief on the origination of it.  If you question most people and ask them if energy is absorbed or released when you break bonds, they will usually say released.  This misconception (as Dr. Funck) believes comes from Biology and the teaching that “Breaking ‘high energy’ bonds in the hydrolysis of ATP releases energy.”  That is a total misconception – any time you break bonds you need energy or energy must be absorbed (endothermic).  When you form bonds, there is a releasing of energy (exothermic).  He says to show this to students with Morse Diagrams and that there is no net change in the energy of the bonds in the hydrolysis of ATP and that what needs to be taken into account is the Gibbs Free Energy.

I think you need each student to experience this through simulations and continual higher-order questioning until they throw that misconception out of their head.

Question 6 – This gas laws/kinetics question showed that students had trouble clearly and concisely detailing what happened molecularly (according to the Kinetic-Molecular Theory) on why the pressure will increase when temperature increased.  Most students had misconceptions (probably due to the invisible nature of gases) and could explain it with gas laws but not what is truly happening to the molecules.  Students also had a tough time with zero order reactions.

Session Big-Point:  Identify common misconceptions and attack them consistently and through different teaching methods of presentation.