If you are reading this you probably already know that the AP system as a whole is undergoing an extensive re-write, and that AP chemistry is in line to have its new curriculum come into play within the next few years. Currently there is no official date for the start of the new syllabus, but August of 2013 looks like the earliest possible date for the introduction of the new chemistry course, with the new exam implemented no sooner than May of 2014, and maybe even later than that. It’s taken since at least June of 2008 to get to this point, so who knows how much more time before the new exam gets here?

A few weeks ago I got a sneak peek at the latest document to outline the new curriculum; the first time I have seen official word on the chemistry content. I have taken the time to read the draft and here is a summary with some comment and analysis.

Introduction

The document starts with stating what we already know, i.e. that there will be an attempt on the new exam to shift the emphasis away from so much content and toward inquiry, deeper understanding and ‘a model of instruction that promotes enduring conceptual understandings and the content that supports them’. Quite what all that means is largely beyond me, and quite how the exam is going to examine such ‘enduring conceptual understanding’ is not at all clear (oh, BTW, it can’t!), but it all sounds tremendously well-intentioned and in line with 21st century ‘edubabble’.

Content

The new content is organized under six broad headings called Big Ideas. The Big Ideas are further sub-divided into, Enduring Understandings and Essential knowledge. Quite what these grand titles precisely mean is not clear to me either (at least not outside the context of ‘edubabble’), but they strike me as simply dressing up a list of stuff that the kids need to know, but remain largely meaningless in themselves. In addition to these there are Learning Objectives which, and I quote, ‘provide clear and detailed articulation of what students should know and be able to do’. That sounds a LOT like this which has been around for over a decade and didn’t take me six years to write!

What is certainly more useful is the introduction of Exclusion Statements. These statements specifically list things that will not be tested on the exam, and this IS most definitely useful information. Having said that, these statements should really be unnecessary IF the content that CAN be examined, is well-defined. As you’ll see later in this post, for the first time in the history of the AP chemistry exam there actually IS a really well-defined list of content objectives, so the irony of NOW providing exclusion statements (not really needed now, but desperately needed in the past) is fairly thick! Anyway, they will still be helpful to those less familiar with the exam than the experienced practitioner, so I suppose we should be grateful. It would appear that the exclusion statements are basically a formalization of the list of things that have been rumored would be removed from the exam over the last few years.

The Big Ideas

Each Big Idea in the draft document is followed by a number of enduring understandings, essential knowledge statements and learning objectives. I have attempted to summarize each of the big ideas those below and in each case I have tried to outline what I see as NOT changing much when compared to the current AP content, new, different or perhaps re-emphasized in a manner not clear in the past when compared to the current AP content, and what will be excluded in the future (i.e. the exclusion statements).

Big Idea #1. Structure of Matter: The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions.

• NOT changing much: Atomic theory, stoichiometry (including the usual with emphasis on gravimetric analysis, titrations, Beer’s law), electronic configuration, periodicity

• New, different or perhaps re-emphasized in manner not clear in the past:

1. Coloumbs’ Law explicitly mentioned including  [math]F = q1q2/r^2[/math] so whilst I DO mention this now, it would appear that there is a little extra emphasis and perhaps the potential for rudimentary, quantitative questions in the future.
2. Photoelectron spectroscopy (PES) is specifically mentioned, but it may be that this is no more than simply reiterating the theory behind the application of E = hν, the Rydberg equation and c = νλ.
3. Reference to the use of experimental results to refine models in science. I suspect that this is something that all competent teachers do anyway, either via implication or explicit intent, but it is apparently being emphasized here.
4. Specific reference to mass spectrometry in relation to the existence of isotopes.
5. I’m not sure I really understand learning objective LO 1.15 which says, “The student can justify the selection of a particular type of spectroscopy to measure properties associated with vibrational or electronic motions of molecules’ – it sounds like it’s asking about when one should use infra-red, UV and ¹H-NMR but at the same time I’m fairly positive that it doesn’t mean that!

• Excluded:

1. Exceptions to the Aufbau principle (which I have always taken to mean only groups 6 and 11).
2. Quantum numbers.

Big Idea #2. Properties of Matter: Chemical and physical properties of materials can be explained by the structure and the arrangement of atoms, ions, or molecules and the forces between them.

• NOT changing much: Solids, liquids and solutions, inter-particulate interactions relating to properties, gases, ionic, covalent and metallic bonding, electronegativity, VSEPR and Lewis diagrams

• New, different or perhaps re-emphasized in manner not clear in the past:

1. Viscosity, capillary action and surface tension mentioned specifically. I know many teachers touch on this anyway, but I don not recall an AP question ever asking about these things in a specific manner in the past (even given H-bonding is often related to viscosity).
2. Colloids and particulate size are mentioned specifically.
3. More than on specific reference to distillation, chromatography and the ability to design/interpret experiments that are used for separation.
4. Reference to electrostatic (Coulombic) forces in ‘active sites in enzyme catalysis’ and ‘hydrophilic and hydrophobic regions in proteins that determine three-dimensional structure in water solutions’. Sounds like biology to me, and has definitely never formed part of an AP chemistry exam. This seems like a deliberate attempt to show a real-world application of intermolecular forces which forces the syllabus OUTSIDE of the confines of traditional chemistry and into biology. As such, I don’t like it.
5. Specific reference to the hydrogen molecule, potential energy versus nuclear distance graph.
6. The use of term hybridization UP TO sp3. (This reflects the recent developments that suggest hybridization models beyond sp3 are of limited value). The syllabus states that shapes of species that have more than four centers of negative charge can still be asked, but their hybridization will not be.
7. A very brief ‘nod’ to molecular orbital theory BUT no need for diagrams or filling so essentially nothing at all and therefore apparently no real change to the current situation.
8. Alloys are perhaps given a little more attention than most teachers would normally bother with currently.
9. Silicon specifically mentioned in relation to doping and semi-conducting properties.

• Excluded:

1. Colligative properties.
2. Molality calculations.
3. Mass percent and percent by volume as applied to solutions (although I cannot recall these being examined at all, recently).
4. Knowledge of specific types of crystal structure (which I assume relates to ABC, ABA etc. and BCC, FCC etc. In my mind, and indeed my practice, this has ALWAYS been excluded since it’s never been examined!
5. Formal charge as used to explain why octet rule is not followed. (Formal charge as an entity for selecting a more favorable Lewis structure is still ‘in’, though).
6. Hybridization beyond sp3 – see #6 above.

Big Idea #3. Chemical Reactions: Changes in matter involve the rearrangement and/or reorganization of atoms and/or the transfer of electrons.

• NOT changing much: Equation writing (molecular, ionic, net ionic), limiting reactant, % yield, Brønsted-Lowry acid base theory, simple redox (including half-reactions), oxidation numbers, identification of those reactions, endothermic and exothermic definitions, Electrochemistry

• New, different or perhaps re-emphasized in manner not clear in the past:

1. It remains to be seen how writing equations will be examined in the future.
2. Redox titrations emphasized in more than one place.
3. The idea of a redox reaction being an energy producing process is noted.

• Excluded:

1. Lewis Acid/Base theory.
2. Apparently the ‘language of reducing agent and oxidizing agent is beyond the scope of this course and the AP exam’! Quite what the sense behind that exclusion statement totally escapes me!
3. Labeling electrodes as positive or negative (haven’t seen that in forever, anyway).
4. Nernst Equation.

Big Idea #4. Rates of Chemical Reactions: Rates of chemical reactions are determined by details of the molecular collisions.

• NOT changing much: Rates of reaction

• New, different or perhaps re-emphasized in manner not clear in the past:

1. A specific reference to Beer’s Law being used to measure concentration change over time and therefore as a method of measuring a rate.
2. There seems to be a very deliberate distinction made between a catalyst stabilizing a transition state/lowering an activation energy and a catalyst participating in the formation of a new intermediate/creating a new pathway, as two very separate functions. In addition there is specific reference to acid/base catalysts, surface catalysts and enzymes.

• Excluded:

1. Calculations involving the Arrhenius equation (when was the last time this was asked on an AP exam anyway?)

Big Idea #5. Thermodynamics: The laws of thermodynamics describe the essential role of energy and explain and predict the direction of changes in matter.

• NOT changing much: Kinetic theory, specific heat capacity, heating & cooling curves (ΔH vaporization and fusion), calorimetry and enthalpy changes, intermolecular forces, entropy and Gibbs free energy, equilibrium (in relation to G)

• New, different or perhaps re-emphasized in manner not clear in the past:

1. More emphasis as heat being a transfer of energy in a process to establish equilibrium that I have seen in the past.
2. The syllabus specifically mentions calculations relating to work in relation to change in gas volume. Now, although we have seen work tested in the deep, deep distance past, this would be a re-adventure.
3. Reiteration of the use of energy versus distance between atoms to find bond length and strength.
4. An apparent emphasis on inter and intra-bond changes as evidence for physical and chemical change.
5. A note about intermolecular forces of large molecules such as those between polymers, enzyme and other biomolecules – should be easy to identify using H-bonding and polymers as examples.
6. There is (for me) a VERY unsettling (and in my opinion unnecessary) reference to ATP/ADP/coupling in biochemical reactions in a Gibbs free energy that I could do without! I’m not a biologist.
7. The phrase ‘Thermodynamically favored’ will be used instead of ‘spontaneous – a good thing IMO.
8. Use of an external energy source to make non-spontaneous reactions occur is not new (electrolysis and re-charging batteries), BUT the specific mention of light (photosynthesis and ionization) seems to be quite pointed.
9. The phrase ‘Kinetic Control’ appears to have replaced ‘Kinetically Stable’ in the vocabulary of the syllabus.

• Excluded: Not much
  

Big Idea #6. Equilibrium: Any bond or intermolecular attraction that can be formed can be broken. These two processes are in a dynamic competition, sensitive to initial conditions and external perturbations.

• NOT changing much: Equilibrium and Le Chatelier’s Principle, Acid Base equilibria (pH, pOH, Kw, Ka, Kb, titration, titration curves, buffers etc.), Ksp, Delta G and K

• New, different or perhaps re-emphasized in manner not clear in the past:

1. I like the idea of identifying some weak acids and bases in a specific way.
2. A note about applications of pH in relation to the protonation of protein side chains
3. ANOTHER biological reference to exergonic and endergonic – MORE biology??

• Excluded:

1. Calculations relating to polyprotic acids.
2. Calculations involving the change in pH when buffers are disturbed. So I assume that a question such as 1993, 1(c) could now, not be asked.
3. I’m not sure I follow this exclusion statement; ‘Production of the Henderson-Hasselbach equation by algebraic manipulation of the relevant equilibrium constant expression is beyond the scope of this course and the AP exam’. Given the HH equation has always been printed on the data packet (equation sheet) that comes with the exam, I’m not sure that any student has ever bothered to derive it in the exam! My guess is that maybe the HH equation will be removed from the data packet in the future. For the record I will continue to teach it, AND expect to be given full credit for using it. It WORKS!
4. With the exception of knowing that all Na, K, ammonium and nitrate salts are soluble, other solubility rules will not need to be learned.
5. It would appear (although I am not 100% sure) that one of the exclusion statements suggests that calculations involving the phenomena of ‘common ion’ will not be tested.

The document ends with a list of seven science practices which apparently just glorified statements of scientific habits which although are important are what (good) teachers are teaching anyway. They really have no bearing on the content, and I suspect will have little (or no) bearing on the examination itself.  If you want to read more on the Science Practices and another perspective, earlier this week Chemical and Engineering News ran a story on the new AP curriculum that can be found at the links below.

Renewing Advanced Placement

Big Ideas and Science Practices

Overview

Everything in the overview should be couched in the fact that I have not seen any more than just a few example multiple-choice questions, and that all of this is of course still provisional, but IF the training and ramp-up to getting this on the ground for teachers is really going to be done properly, the document that I saw MUST be at least close to the final version – it would have to be if this is coming down anywhere near August of 2013. IF the first rendering of the new exam is in May 2014, teachers must start teaching the new course in August of 2013, and realistically need to have training, AND CRUCIALLY EXAMPLE EXAM QUESTIONS in the summer of 2012, i.e. in about 9 or 10 months time.

There are several references to models, diagrams, symbolic representations and particulate drawings that suggest an emphasis on those things. I have seen a few examples of multiple-choice questions as well, and they seem to reflect the idea that diagrams are going to be used a lot to explain certain phenomena.

To be honest it doesn’t look like the content is being reduced very much at all. As I have said over and over again, the ONLY way to test experimental design skills and interpretation is to have a lab exam, so following the first dog & pony show attempt (AKA the audit), this looks like the latest idea to try to force more lab situations on to the exam without doing it properly (lab exam).

It really doesn’t look as though there is a significant reduction in the breadth of the chemistry, especially since there have been a number of biological references added.

Most competent teachers will take this all in their stride, but even the best teachers need to know how all of this will manifest itself in the new, written exam and in that respect we desperately need example exam questions as soon as possible. Without them we are somewhat shooting in the dark, and that’s just not on. Given the horrendous, teeth-pulling exercise that extracting examples of the new net ionic equations was in 2007, I don’t hold out much hope of this coming easily.

Right now (with somewhat limited data) I don’t see the ability to ‘coach’ kids through the lab situations without necessarily doing them is going to change much if at all. There is clearly going to be a greater emphasis on experimental design and data interpretation within the exam itself but this is STILL a pen and paper exercise that can largely be TAUGHT with pen & paper. I guess we’ll see, sometime within the next x years!