5 Comments

1. 

   webmaster on May 15, 2009 at 5:40 am

   A couple of extra points since posting at around 6.00 PM last night.

   I tidied up the calculations in question 2 in terms of sig figs and I added the the principal quantum number “3” to my answer to question 6(c) (thanks Ben). Hopefully that will not be necessary to get all of the points, but we’ll see.

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2. 

   Modox on May 15, 2009 at 9:27 am

   In 6(c) I understand 3p as the answer given “atomic” as the qualifier, but is this, in fact, true about H2S? It appears that I never learned this, if true – I’ve been teaching H2S as an example of sp3 hybridization of sulfer with a (less than) 109.5 degree bond angle. I’m confused and surprised that I missed this!

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3. 

   webmaster on May 15, 2009 at 10:11 am

   Modox writes;

   >In 6(c) I understand 3p as the answer given “atomic” as the qualifier, but is this, in fact, true about H2S? It appears that I never learned this, if true – I’ve been teaching H2S as an example of sp3 hybridization of sulfer with a (less than) 109.5 degree bond angle. I’m confused and surprised that I missed this!

    

   Well, without “looking it up” I have NO idea, and frankly nor should I (NOR should you)! There is NO way that this question is going to be asked WITHOUT the qualifier of giving the bond angle, which in turn suggests that sp³ hybridization is NOT the answer. I think that using the word “atomic” is going too far since it gives the game away. My point is that there is no way this “factoid” about H₂S is going to be part of the “normal” knowledge base of AP teachers let alone AP students.

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4. 

   Modox on May 15, 2009 at 10:55 am

   Well, then I totally agree – I do not understand why this question would be asked on an AP exam!

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5. 

   Joseph on May 15, 2009 at 11:16 am

   Question 1 has a typo. Part (d) section (ii) is incorrectly identified.

   Thanks for your work; I look forward to grading the exam this year for the first time.

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