6/14/14%
Chemistry of Solutions
202-NYB-05
Chapter 12: Chemical Kinetics
What is Chemical Kinetics?
! It is the study of the speed (rate) at which a
reaction occurs
! It Allows us to obtain an understanding of the
reaction mechanism.
! the reaction mechanism can be used to see
which step is the slowest and see if we can speed
it up.
! Factors affecting reaction rate:
Concentrations of reactants
Catalyst
Temperature
Surface area of solid reactants or catalyst
1%
, 6/14/14%
3
Chemical Kinetics
Example of spontaneous and slow:
2H2(g) + O2(g) 2H2O(l)
However, if you add a spark, reaction rate
becomes extremely rapid.
Image Obtained from:
http://www.aerospaceguide.net/
spacepictures/shuttle_endeavour.jpg
Factors That Affect Reaction Rates
! Concentration of Reactants
! As the concentration of reactants increases, so does the likelihood
that reactant molecules will collide.
! Temperature
! At higher temperatures, reactant molecules have more kinetic energy,
move faster, and collide more often and with greater energy.
! Catalysts
! Speed rxn by changing
mechanism.
2%
, 6/14/14%
Reaction Rates
Rxn Movie
Rates of reactions can be determined by
monitoring the change in concentration
of either reactants or products as a
function of time. Δ[A] vs Δt
6
Reaction Rate Defined
Reaction rate: changes in a
concentration of a product or a reactant
per unit time. []
Δ[ ] concentration
Reaction rate = ——
Feactants
Δt
[A] − [A]o Δ[ ]
Rate =
t − to
Δt
Define reaction rate and explain
Average reaction rate
Instantaneous reaction rate
(2 tangents shown)
€ Initial reaction rate t
3%
, 6/14/14%
7
Reaction Rates
seitan
-
-
( )
=- 4.2x10-5 mol/L.s
8
Reaction Rates
C4H9Cl(aq) + H2O(l) ""→ C4H9OH(aq) + HCl(aq)
[C4H9Cl] M
In this reaction, the
concentration of
butyl chloride,
C4H9Cl, was
measured at
various times, t.
4%
Chemistry of Solutions
202-NYB-05
Chapter 12: Chemical Kinetics
What is Chemical Kinetics?
! It is the study of the speed (rate) at which a
reaction occurs
! It Allows us to obtain an understanding of the
reaction mechanism.
! the reaction mechanism can be used to see
which step is the slowest and see if we can speed
it up.
! Factors affecting reaction rate:
Concentrations of reactants
Catalyst
Temperature
Surface area of solid reactants or catalyst
1%
, 6/14/14%
3
Chemical Kinetics
Example of spontaneous and slow:
2H2(g) + O2(g) 2H2O(l)
However, if you add a spark, reaction rate
becomes extremely rapid.
Image Obtained from:
http://www.aerospaceguide.net/
spacepictures/shuttle_endeavour.jpg
Factors That Affect Reaction Rates
! Concentration of Reactants
! As the concentration of reactants increases, so does the likelihood
that reactant molecules will collide.
! Temperature
! At higher temperatures, reactant molecules have more kinetic energy,
move faster, and collide more often and with greater energy.
! Catalysts
! Speed rxn by changing
mechanism.
2%
, 6/14/14%
Reaction Rates
Rxn Movie
Rates of reactions can be determined by
monitoring the change in concentration
of either reactants or products as a
function of time. Δ[A] vs Δt
6
Reaction Rate Defined
Reaction rate: changes in a
concentration of a product or a reactant
per unit time. []
Δ[ ] concentration
Reaction rate = ——
Feactants
Δt
[A] − [A]o Δ[ ]
Rate =
t − to
Δt
Define reaction rate and explain
Average reaction rate
Instantaneous reaction rate
(2 tangents shown)
€ Initial reaction rate t
3%
, 6/14/14%
7
Reaction Rates
seitan
-
-
( )
=- 4.2x10-5 mol/L.s
8
Reaction Rates
C4H9Cl(aq) + H2O(l) ""→ C4H9OH(aq) + HCl(aq)
[C4H9Cl] M
In this reaction, the
concentration of
butyl chloride,
C4H9Cl, was
measured at
various times, t.
4%
