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# What's Going On in Your Classes This Week?

Started almost 4 years ago by Kimberly Duncan.

I was just wondering what topics you are covering in your classes this week - especially in AP Chemistry (if you are teaching it). AACT has three webinars coming up in the coming weeks that will focus on AP Chemistry.

The first (March23) focuses on the AP Chemistry Review PowerPoint that was put together by over 30 AP teachers last spring. In the second one (March 28), Paul Price, who is on the AP Chemistry test development team, will talk about buffers, equilibrium, and limiting reactants with special focus on the dreaded question #6 from last years exam. And in the third one (April 5), Deena Leggett will talk about using Peer Instruction to teach challenging concepts. I hope you will check them out in the Professional Development page of the website.

• Kimberly Duncan

Posted almost 4 years ago

The mean score on Question 6 in 2016 was 0.45/4!

Ba
2+
(
aq
) + EDTA
4

(
aq
)
R
Ba(EDTA)
2

(
aq
)
K
= 7.7 × 10
7
6. The polyatomic ion
C
10
H
12
N
2
O
8
4

is commonly abbreviated as
EDTA
4

. The ion can form complexes with
metal ions in aqueous solutions. A complex of
EDTA
4

with
Ba
2+
ion forms according to the equation
above. A 50.0 mL volume of a solution that has an
EDTA
4

(
aq
)
concentration of 0.30
M
is mixed with 50.0 mL
of 0.20
M
Ba(NO
3
)
2
to produce 100.0 mL of solution.
(a) Considering the value of
K
for the reaction, determine the concentration of
Ba(EDTA)
2

(
aq
) in the
(b) The solution is diluted with distilled water to a total volume of
2+
Ba
(
aq
)
1.00 L. After equilibrium has been
reestablished, is the number of moles of
present in the solution greater than, less than, or equal to
the number of moles of
Ba
2+
(
aq
)
present in the original solution before it was diluted? Justify your answer.

• Alyse Riehl

Posted almost 4 years ago

Hi Kim,
I am still working on Kinetics with my students. I did two experiments with them. One in which they designed their own experiment to examine the factors that affect rates of reaction. The other was the Order of Reaction experiment with iodide, persulfate, and hydrogen peroxide. What was the dreaded question six from last years exam? I would definitely like to view the peer instruction one. Also, I have some general knowledge questions for you, but I will ask at a later time (have to go teach now). :)