Unit 6 Kinetics Flashcards
how can rates of reactions be monitored?
finding the change in either the reactants or products
what is the formula to find the rate of production? what is the rate of production of b?
rate=change in concentration over the change in time
e.g rate of B= -(change of concentration of B)/the change in time
what is the rate of consumption formula of A?
rate of consumption of A= -change in concentration of A/t2-t1
what is the sign for the average rate of consumption?why?
negative because the reactants are decreasing as a function of time
what is the rate law formula defintion?
an equation showing how the reaction rate depends on the concentration (moles) of each reactant
what is an example equation of a rate law? what do the numbers to the left and right of the concentrations represent?
rate law=k[A]^m[B]^n
[A] and [B] are the concentrations in M
m is the exponent for A
n is the exponent for B
do the exponents equal the coefficients of each concentration?
no
how must the reaction law be determined?
experimentally
units of rate
M/s
What is the reaction rate?
a measure of how fast the reaction is going
what are integrated rate laws?
mathematical functions that give the concentrations over the change in time
what is half-life?
the time it takes the reactants to reach 50% of its original values
what do reaction mechanisms do?
connect microscopic molecular processes to the overall rate
what does Arrhenius equations decribe?
describes how the rate changes with temperature
what can kinetics reveal about a reaction
how a reaction occurs
what is the graphical method of the rate law? what does the shape of the line reveal
monitor the reaction over time
plot the data
shape of the graph line reveals the order of the reaction
what is the zeroth order formula? does rate depend on concentration?
Rate=k
Rate does not depend on concentration because there is no concentration
What are the conditions of the zeroth order in terms of the graph?
If the graph is linear and going downwards, the reaction is zero order
What is the equation of a straight line for zeroth order (integrated rate law)?
[At]=-kt+[A]o
What is the first-order formula for rates? Does rate depend on concentration?
Rate=k[A]
Rate does depend on the concentration
What is the second order formula for Rate?
Rate=k[A]^2
What happens to the concentration when you double the rate of a second order reaction?
- Apply the exponent to the rate side with the base 2
The reaction will quadruple
What does the half-life depend on? what happens to the half-life in terms of amount?
Dependent on intial concentration
Gets shorter over the course of the reaction
what is the Integrated Rate law for first-order reactions?
Ln[A]=-kt+1/[Ao]
what is the Integrated Rate law for second-order reactions?
1/[A]=kt+1/[Ao]
What is the equation for half-life for the first-order reaction?
t1/2=ln2/k
What does it mean if the graph is linear and goes down
The reaction is first order
What does it mean if the graph is linear and going up?
The reaction is second order
What is the half life formula of the second order reaction
t1/2=1/k[A]o
What are the conditions of the half-life second-order reaction?
t1/2 depends on the intial concentration
t1/2 gets longer over the course of the reaction
what is the half-life formula for a zero-order reaction?
t1/2=[A]o/2k
