Adrian Dingle’s Chemistry Pages - The Blog

Subscriber Updates

If you have a subscription to either the Regular or the Honors Worksheets, you will notice that links have been added for answer sheets. These are a new feature and an addition to the package that I trust will enhance the worksheets. It will take time for all of the answer sheets to appear, however they will be added on a regular basis.

Newsletter #2

Newsletter #2 can now be read, here.

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AP Scores 2010 - Best EVER!

The AP scores for my chemistry classes have now been received and the average score is the best that my students have ever recorded. A total of 34 students scored 31 “5’s” and 3 “4’s” for an average of 4.91.

Nice work and congratulations to all.

Subscriber Updates

All relevant subscribers have had the 2010 AP Worked Answers added to their subscriber areas.

Newsletter #1

Newsletter #1 can now be read, here.

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Subscription discounts through August 1st, 2010

I’m offering a 15% discount on all subscriptions purchased through August 1, 2010.

Details here; Subscriber pages

Simply purchase as normal, and within 48 hours receive a 15% PayPal refund.

Subscriber Updates

Organic materials in TOPICS 1-5 have been updated in the relevant subscriber areas.

My new book finally sees the light of day

After several delays it appears as though my new book will be available for purchase in October 2010. The preview of, “How To Make A Universe With 92 Ingredients”, is now on Amazon.com;

http://www.amazon.com/How-Make-Universe-92-Ingredien/dp/1407117912/ref=sr_1_1?ie=UTF8&s=books&qid=1276861195&sr=8-1

2010 Exam Comments and DRAFT Answers

Below you will find my comments on the 2010 AP chemistry exam, and my DRAFT answers. PLEASE NOTE: The answers are my first draft and I will be very happy to receive comments and corrections. Thanks go out to an AP reader for taking a look and making suggestions - you know who you are.

Comments:

Question 1:
Standard fare. Lacks much imagination, I’m afraid.

Question 2:
Very, very easy.

Question 3:
Very, very easy.

Although it makes no difference to the question, the production of Mn3+ in the half-reaction where manganate(VII) is an oxidizing agent, seems a little esoteric and unnecessary to me. Now, perhaps under some circumstances it DOES do that, but in every reference I have ever seens at this level I have only ever witnessed it turning into Mn2+. In addition, Greenwood & Earnshaw, Chemistry of the Elements (known as the “green brick” and my go to guide on such matters) suggests that Mn2+ is the usual product. (G&E DOES mention that one “preparative route” to Mn3+ is “reduction of KMnO4″, but it also notes that Mn3+ has a “marked tendency to disproportionate”. My gripe here is NOT really about the chemistry (whatever it may be), but rather about the wisdom of suddenly having Mn3+ turn up as a product of the acid reduction of Mn7+ instead of (infinitely more usual) Mn2+. It seems like an unncessary diversion and something that could confuse potentially excellent candidates. It just doesn’t make much sense to me.

Question 4:
It seems as though the question writers have given up on this part of the exam. Possibly the easiest EVER? Why GIVE the colors in (a)(ii)? Why tell the kids a gas is produced in (c)(i)? The astonishing decline of complexity in this question in recent years is mildly depressing.

Question 5:
Very, very standard/easy.

(c) Delighted than ethanoic acid seems to finally be supplanting “acetic acid”! Hooray!

Question 6:
Very, very standard/easy.

If this represents a comprehensive and vigorous examination of the best, and highest level of chemistry being taught in American high schools then I think that we have a problem. I remain a HUGE supporter of the public examination/standardized test and its place, but this test simply does not add up to much of challenge at all. Quite weak and disappointing.

ANSWERS

Element 117

http://www.nytimes.com/2010/04/07/science/07element.html