smaerd
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Mood: hmm...
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Basic Kinetics Question(Gen. Chem)
So here's the question.
CHCl3(g) + Cl2(g) -> CCl4(g) + HCl(g)
Rate-law: Rate = k*[CHCl3]*[Cl2]^(1/2)
What is the overall order and the units of the rate constant for the reaction?
The overall order is 3/2 no problem there  .
The problem I'm having is this. The CHCl3 is a first order reaction(Unit = 1/S) while the Cl2 is a 1/2 order reaction. In my book it has what a Zero
order, First Order, and Second order reaction are but mentions nothing of non-integer order reactions. What am I supposed to do?
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Magpie
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Quote: Originally posted by smaerd  |
CHCl3(g) + Cl2(g) -> CCl4(g) + HCl(g)
Rate-law: Rate = k*[CHCl3]*[Cl2]^(1/2)
What is ... the units of the rate constant for the reaction?
What am I supposed to do? |
The units of k are whatever are needed to provide equal units on both sides of the equation.
So, presuming the units on the left are moles/(liter-s) the units for k are [(moles/liter)^(-1/2)]/s.
The single most important condition for a successful synthesis is good mixing - Nicodem
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smaerd
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Well the answer he provided was 1/(S * M^(1/2)) and I'm just not seeing it.
His work shows this: K = M * S^(-1) / M ^(3/2)
I have no idea where the 3/2 came from, one is first order and one is 1/2 order? Unless its from the overall order?
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Magpie
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| Quote: Originally posted by smaerd | Well the answer he provided was 1/(S * M^(1/2)) and I'm just not seeing it.
His work shows this: K = M * S^(-1) / M ^(3/2)
I have no idea where the 3/2 came from, one is first order and one is 1/2 order? Unless its from the overall order? |
The answer he gave is the same as the one I gave where M=moles/liter, and S = s.
K=M*S^(-1)/M^(3/2) = M^(-1/2)/S = 1/(S*M^(1/2))
K is just a constant that provides equality based on the units (dimensions) that were chosen. It could just as well have been expressed in
(molecules/gallon)/hr.
The single most important condition for a successful synthesis is good mixing - Nicodem
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smaerd
International Hazard
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Registered: 23-1-2010
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Mood: hmm...
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Oh wow I feel retarded.
This is what happens when you study calculus 2 for 5 hours then try to hop straight into chemistry. You confuse yourself lol. Didn't help that my
professor covered the chapter in 3 one hour class periods. Thanks for bearing with me. Much appreciated. Kinda let down that I couldn't see that...
[Edited on 20-2-2011 by smaerd]
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