Chapter 14 - Chemical Kinetics Flashcards
What is chemical kinetics?
The area of chemistry in which reaction rates are studied.
What 4 factors affect the reaction rate?
- Physical state of reactants
- Concentration
- Temperature
- Presence of catalysts
How are reaction rates usually expressed?
Molarity/second (M/s).
What generally happens to a reaction rate as time passes?
It slows down.
What is the instantaneous rate?
It is the slope of a line drawn tangent to the concentration-versus-time curve at a specific time.
How is a rate law calculated?
Rate=k[A]^m[B]^n
A and B=molarity
m and n=order of reaction
How do you calculate the overall reaction order?
You add the reaction orders together (m+n=overall).
What is a first order reaction like?
When the rate is proportional to the concentration of a single reactant raised to the first power.
How is a first order reaction calculated?
Rate=k[A]
Integrated rate:
ln[A]t=-kt+ln[A]0
What is a second order reaction?
One for which the overall reaction order is 2.
How is a second order reaction calculated?
Rate=k[A]^2
Integrated rate:
1/[A]t=1/[A]0+kt
What is a zero order reaction?
One for which the overall reaction order is zero.
Rate=k
What is the half-life of a reaction?
The time required for the concentration of a reactant to drop to one-half of its original value.
How is the half-life of a first order reaction calculated?
0.693/k or ln(2)/k
How is the half-life of a second order reaction calculated?
1/(k*[A]0)
