# Kinetics

• Created by: Em.sp8
• Created on: 27-04-15 09:59

## Rate Definitions

Rate of Change: Change in concentration in a given time.

Rate Constant: Specific for evey reaction at a given temperature (k)

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## Order

Overall Order of Reaction: The sum of the orders of all species in the rate equations.

Zero Order: Not found in rate equation, the rate is independent of this value.

First order: The rate is directly proportional to rate (r=k[A]^m where m=1)

Second order: The rate of reaction is directly proportional to the vvalue squared (r=k[B]^n where n=2)

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## Rate Equation

Example:

A+B C

so r=k[A][B]

so to find k you rearrange k=r/[A][B] so the units are (mol/dm3)/(mol/dm3.mol/dm3) meaning that k units=mol-1dm3s-1

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## k and temperature

• Increasing the temperature increases k
• When the temperature increases by 10 degrees the value of k will double.

In a reaction involving more then one step then one step will be slower then all the rest. This  step limits the overall rate of reaction so is known as the rate determining step.

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