 Hannah
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North_Dakota_Wheat
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Jacob
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Sunday, November 09, 2003
Breaking Down an Equation
How do you own an equation rather than letting it own you. First break it down. That is figure out how many different kinds of question could be asked from that equation, and know how to solve all of them. Consider the first order rate equation for chemical reaction kinetics.
Example:
Start by listing down the question you could ask:
1) Find t
2) Find k
3) Find Ao
4) Find A
5) Find %A
6) Find %P
A) How long would it take to complete 80% of the reaction given the k = 7xE02 sec-1?
B) An experimenter started a half liter with a [5] molar solution of material and when the reaction was monitored in 45 minutes only 1.2 moles remained. Compute the rate constant.
C) What was the initial concentration of the substrate if after 30 minutes the concentration was 30uM and the k=5xE-03 sec-1?
D) What is the concentration of substrate after 1 hour in problem B?
E) What percentage of substrate remains after 20 minutes when the k = 8xE-05?
F) What percentage of the product remains after 10 minutes from the setup in problem E? Problem C?
G) Compute the time it take for half the substrate to be consumed when the rate constant is k=7.5xE-02?
Now answer all the questions for the second order equation:
1/[A] = 1/[Ao] + kt
Could all the questions be answered? Why not?
How do you own an equation rather than letting it own you. First break it down. That is figure out how many different kinds of question could be asked from that equation, and know how to solve all of them. Consider the first order rate equation for chemical reaction kinetics.
Example:
Start by listing down the question you could ask:
1) Find t
2) Find k
3) Find Ao
4) Find A
5) Find %A
6) Find %P
A) How long would it take to complete 80% of the reaction given the k = 7xE02 sec-1?
B) An experimenter started a half liter with a [5] molar solution of material and when the reaction was monitored in 45 minutes only 1.2 moles remained. Compute the rate constant.
C) What was the initial concentration of the substrate if after 30 minutes the concentration was 30uM and the k=5xE-03 sec-1?
D) What is the concentration of substrate after 1 hour in problem B?
E) What percentage of substrate remains after 20 minutes when the k = 8xE-05?
F) What percentage of the product remains after 10 minutes from the setup in problem E? Problem C?
G) Compute the time it take for half the substrate to be consumed when the rate constant is k=7.5xE-02?
Now answer all the questions for the second order equation:
1/[A] = 1/[Ao] + kt
Could all the questions be answered? Why not?
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