Catalyst: chemical agent that speeds up a reaction without being consumed by the reaction → can be used over and over again ○ Do not affect the free energy/enthalpy of a reaction! ○ Reactions with a catalyst will typically require at least 2 steps...
The slowest (rate-determining) step in a mechanism will have the highest activation energy ○ On graph, will have the highest peak Number of peaks = number of elementary steps Intermediates are found in minimums of graph; the transition states are found in...
Determining Rate Law When Slow Step is Not First Write rate law for slow step For fast step: set the rate of the forward reaction (k₁) = rate of reverse reaction (k₋₁) Then solve for the [intermediate] Plug in the equation into the slow step
The rate of a reaction can be no faster than the slowest step We cannot use the coefficients from a balanced, overall equation to deter mine the orders of a reaction ○ Ex: We can use the coefficients from an elementary reaction determine the orders of a...
Activation energy: Activated Complex - Change in Reactants (peak - line) Transition state/Activated complex: bonds are partially formed (shown on curve’s peak) Activation energy of reverse reaction: Forward Activation Energy - | ∆𝐻 | ∆H/∆E (total energy change/energy...
Collision Model: the energy (for breaking bonds of reactants) comes from the kinetic energies possessed by the reacting molecules before the collision ○ Key idea: the rate of a reaction depends on the number of successful collisions and these collisions...
Reaction Mechanisms A chemical equation does not tell us how reactants become products ○ Simply a summary of the overall process Elementary steps: series of steps by which a chemical reaction occurs ○ Cancel out identical species on opposite sides...
First-Order Rate Law Order = 1 → changing the reactant concentration has an identical effect on the reaction rate (same factor) Rate Law = If a plot of ln[A] versus time is a straight line → reaction is first order Integrated First Order rate law: (on reference...
Initial Rate Method: the “instantaneous rate” just after the reaction beings; Usually the fastest ○ K = rate constant; m and n = rate orders Rate Constant (k): relates the rate of the reaction to the concentration of the reactants = slope ○ Value...
Spontaneous reactions: reactions that will happen but we cant tell when or how fast Kinetics: the study of the rates of a chemical reaction Can determine the coefficients of the chemical equation when given graph of concentration vs time by doing: ○ The...