Adrian Dingle’s Chemistry Pages - The Blog

Book reviews and news

My book is now getting some great press, and is becoming quite a hit - for a humble chemistry teacher it’s really quite a thrill!

It has been reviewed here;

1. New Scientist; http://www.newscientist.com/article.ns?id=mg19425992.200&feedId=fundamentals_rss20c

2. Teens Read Too; http://www.teensreadtoo.com/PeriodicTable.html

3. Publishers Weekly; http://www.publishersweekly.com/article/CA6420421.html?nid=2788

More here news here, including a nomination for the American Library Association 2008 YALSA Quick Picks for Reluctant Young Adult Readers List;

http://www.ala.org/ala/yalsa/booklistsawards/quickpicks/quickpick.htm

You can purchase the book here;

http://www.amazon.com/Periodic-Table-Elements-Style/dp/0753460858/sr=8-4/qid=1162993002/ref=sr_1_4/103-7024614-8991055?ie=UTF8&s=books

Looking for answers to the 2007 AP exam?

These have now rotated off the site and are only available as part of subscription package #9 or #11, here;

www.adriandingleschemistrypages.com/subscriber.html 

The recent fuss over units of “kJ per mole of REACTION” on 2007, 2

Having analyzed all of the comments (both off and on the AP listserve) in regards to this matter, the following are perfectly clear to me;

1. James Spencer’s article actually makes a decent argument for using the “kJ per mole of reaction” in TERMS OF CHEMISTRY and the units of Delta G. For the record I don’t like it much, but if I had to live with it I would.

2. This concept is NOT being used with ANY kind of regularity amongst common AP texts nor in AP classrooms across the country. MANY, VERY experienced teachers are simply not on board with this nomenclature. As a result, to say this is potentially confusing to candidates is a HUGE understatement.

3. #1 notwithstanding, the College Board/Test Development Committee has made a serious error here by NOT introducing the relevance of this concept to the exam in a MUCH, MUCH, MUCH bolder way. ANOTHER horrible effort at communicating with those of us on the ground.

4. #3 is EXACTLY the same kind of error that the CB/TDC made when not properly introducing examples for the new question #4 format - that was a shambles, so is this. There appears to be a disconnect between the TDC and the teachers.

In summary, there may not necessarily be any problem with the chemistry in this instance, and in that respect I disagree with some of my more upset colleagues, but you simply cannot conduct public examinations and standardizing testing in this manner.

2007B AP Free Response DRAFT Worked Answers

My DRAFT 2007B Worked Answers are now available here;

2007B, 1

2007B, 2

2007B, 3

2007B, 4

2007B, 5

2007B, 6

PLEASE, feel free to comment, point out mistakes and generally be critical!

Dingle’s Comments on the 2007B AP Exam

In general significantly harder than the “A” form.

Question #1

Glad to see a Kp question, isn’t it about time this cropped up on the “A” form? I don’t like the fact that the Kp expression is given, but again this signals a general “dumbing down” that we continue to see.

Question #2

No comment required.

Question #3

No comment required.

Question #4

Part (b) again reflects the “dumbing down” by stating chlorine is the oxidizing agent.

Question #5

I WISH we could leave “Lactic Acid”, “Acetic Acid” and “Acetate” behind once and for all – these are NOT the modern names.

In part (b) I would like have seen a dropper added to the equipment list for accurate “making up to the mark” AND perhaps a funnel, wash bottle and a weighing boat since I would weigh the solid into a weighing boat, then use the wash bottle to transfer the solid through the funnel into the volumetric flask before making carefully up to the mark with the dropper.

In general, this question reinforces the FACT that it is not possible to examine lab techniques/knowledge in a meaningful way WITHOUT a lab exam.

Question #6

Parts (c), (d) and (e) WAY too easy.

Subscriber Update

All subscriptions that include the 2000-06 AP Worked Answers have now had the 2007 AP Worked Answers added free of charge, and, as a result, have now become 2000-07 subscriptions!

Dingle’s Comments on the 2007 AP Exam

Question #1 

Parts (c), (d) and (e) – Indicative of the recent trend for the dumbing down of the exam – rather than getting the students to work out that a buffer solution is present, the fact that calculations relating to the concentrations of the remaining acid and salt are included BEFORE asking the pH, mean that there is a lot of hand holding and guiding students to the correct answer. For a comparison take a look at 1996, 2(c) where a similar question was asked (pH of a buffer) but no such specific clues were given.

Question #2

The “per mole” part of the units for DH and DS will definitely screw up some candidates calculations. Again, part (d) is the type of HUGE clue to part (e) that we are beginning to see more and more of and never did in the past. (If you have any doubt, take a look at 1996, 3(d) for comparison purposes).

Question #3

No comment required.

Question #4

As I predicted, hopelessly easy. Part (a)(ii) will cause a headache at the reading since I feel many students will interpret the question to mean that they should include the moles of NaNO₃ “formed”. I think this is a poorly worded question and the examiners have given themselves an unnecessary headache – I am surprised that it got on to the exam paper. The third example of the dumbing down occurs in part (c). The excellent candidates are being penalized by the exam telling the students about oxidizing and reducing agents – this levels the playing field to too great a degree and such clues have seldom been given in the past (according to my records this has only happened three times before; 1968, 1978 and 1979) and I don’t think such blatant help SHOULD be provided.

Question #5

Parts (d) and (e) continue the “dumbing down” theme. In part (d)(iii) the formula is set-up to make part (e) ridiculously easy. In the past there has never been so much hand-holding and direction for determining the effect of experimental error (see 1999,5(e) as an example).

Question #6

No Comment required.

2007 AP Free Response DRAFT Worked Answers

My DRAFT 2007 Worked Answers are now available here;

2007, 1

2007, 2

2007, 3

2007, 4

2007, 5

2007, 6

PLEASE, feel free to comment, point out mistakes and generally be critical!

Subscriber Update

The following AP Worked Answers have been updated in the relevant subscriber areas;

1994, 6; 1996, 6; 1999, 6; 2002, 3; 2003, 3; 2003, 7

Subscriber Update

The following AP Worked Answers have been updated in the relevant subscriber areas;

2004, 3; 2006, 1 through 8 inclusive.