Chapter 13 - Conceptual Questions Flashcards
What is the linear graph for a zero order equation?
What is the linear graph for a first order equation?
What is the linear graph for a second order equation?
Identify the order with respect to the reactant, A.
(A—–> products)
The half-life of A is independent of the initial concentration of [A]
1
Identify the order with respect to the reactant, A.
(A —–> products)
A twofold increase in the initial concentration of A leads to a fourfold increase in the initial rate.
2
Identify the order with respect to the reactant, A.
(A —–> products)
A twofold increase in the intial cocentration of A .leads to a 1.41-fold increase in the intial rate.
.5
Identify the order with respect to the reactant, A.
(A-----\> products)
The time required for [A] to decrease from [A]0 to [A]0/2 is equal to the time required for [A] to decrease from [A]o/2 to [A]o/4
1
Identify the order with respect to the reactant, A.
(A-----\> products)
The decrease of [A] is constant
0
What is a catalyst?
- Consumed then reformed
- A catalyst provides an alternative route for the reaction with a lower activation energy.
- It does not “lower the activation energy of the reaction”
.
What is an intermediate?
An intermediate is a sustance which is formed, then consumed in a reaction mechanism.
number of particles vs. energy
(graph)
Label the energy diagram from a two-step reaction
How do energy diagrams for un-catalyzed and catalyzed reactions differ? (graph)
In a reaction mechanism, which reaction determines the rate law?
In a reaction mechanism, the reaction that requires the most energy is the rate-determining step.
(the slow reaction)
What is an “elementary reaction”?
An elementary reaction represents, at the molecular level, a single stage in the progress of the overall reaction.
Their coefficients will be their order in the rate law
What is molecularity in elementary reactions?
The molecularity of an elementary reaction refers to the number of free atoms, ions, or molecules that react.
unimoleluar reaction – an elementary reaction that involves one reactant molecul
bimolecular reaction - an elementary reaction that involves two reactant molecules
termolecular reaction - an elementary reaction that involves three reactant molecules
How do you determine the overall stoichiometry if given a mechanism
1) Add all the products of each elementary step then all the reactants into one giant equation (Hess’s Law)
2) Then remove the intermediates, which are molecules that are formed and consumed in the reaction.
3) Balance the reaction
What is the “rate determining step” (RDS) and how is it related to the overall law?
It is the slow elementary reaction of mechanism.
The elementary reaction can be used to determine the overall law from coefficient, unless intermediates are included, then you’ll have to do some algebra.
How does temperature affect the rate constant k?
Rate constant increases exponentially with temperature.
What is the Arrhenious Equation?
How does activation energy relate to the rate constant?
As activation energy goes up (Ea), rate constant goes down (k)
What is the equation for Beer’s Law?
