Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
What is the principle of microsopic reversibility? |
Energy paths are reversible ( in chemical reaction) |
|
|
What would be the rate formation of A and B: A<->B? |
A=d[A]/dt=-kf[A]+kb[B] B=d[B]/dt=kf[A]-kb[B] |
|
|
Write the chemical kinetic equation to a simple reaction at equilibrium. |
K=Kf/Kb=[B]/[A] this is the equilibrium equation |
|
|
What Happens when K much larger than 1? |
The forward reaction is much favored: Kf/Kb |
|
|
how would you express the rate of change of A for the following? A+B<->C+D? |
d[A]/dt=-kf[A][B]+kb[C][D] |
|
|
What would be the equilibrium equation for the following chemical equation? A+B<->C+D? |
K=Kf/Kb=[C][D]/[A][B] |
|
|
What is a first ordered reaction? what reaction can this be? |
This is an irreversible reaction simply A->B. This can be both chemical or a thermodynamic process. |
|
|
what will be the typical mathematical equation for a first ordered reaction? |
[A]=[A]0e^(-kft) |
|
|
What are two common ways to characterize a first ordered reaction? |
Half life and lifetime. |
|
|
What is the mathmatical equation for the half life? |
T1/2=ln(2)/kf |
|
|
What is the mathematical expression for the lifetime? |
T1/2= 1/Kf |
|
|
What defines the order of reaction? |
the sum of exponents in the rate law. |
|
|
What is the problem with the rate formation of A for the chemical reaction: A+B->C How can you solve it ? |
you end up with: integral A to A0; d[A]/A=integral t to 0; -k[B]dt problem: B is dependent on time while A is dependent on A Solution: assume A=B |
|
|
What is the solution to the second order reaction for a change in product A? |
1/[A]=kt+1/[A]0 |
|
|
What is the lifetime of a second ordered reaction? (A+B->C) |
T1/2=1/k[B] |
|
|
How would you describe the reaction rate of the following: NO+O3->NO2+O2 what is perculliar about this reaction? |
D[NO2]/dt=d[O2]/dt= k[O3][NO] its is a pseudo first order reaction becaus ozone is very high concentration rate=k'[NO] |
|
|
Which of the following reaction could be a pseudo first order reaction: 1;CH3OO+NO->CH3O+NO2 2;CH2O+O2->Ch2O+HO2 3;H2O+O3->OH+2O2 |
2 |
|
|
What would be the lifetime of a third reaction (mathematical equation) and what must you assume. |
t1/2= 1/k[B][C] |
|
|
What is the lindemann-Hinshelwood mechanism reaction? |
A+M->P+M M= is a background molecule ( in the atmosphere it will be N2 or O2) |
|
|
the overall lindemann-Hinselwood reaction is made up of 2 steps: what are they ? |
1:A+M<->A*+M 2:A*-> B+C |
|
|
Lecture 14 LH solution |
now |
|
|
when K1b backwards of the Lindmann-hinshelwood reaction is much larger than K2M what does it look like? |
A third order reaction |
|
|
when K2Mbackwards of the Lindmann-hinshelwood reaction is much larger than K1bwhat does it look like? |
a second order rection |
|
|
Typically, what occurs when O2 is produced from O? |
O and O will collide create a high energy O2 species. This will typically generate a lot of heat and will dissociate after one cycle. The only way to have a stable O2 molecule, it must colide with an M molecule to lower its energy state. |
|
|
Why does O2 is so unstable when first produced? |
There is only one energy bond on which the energy can be stored. This result in high vibrational state and high energy storage. |
|
|
Which will last longuer ? WHy? O2 -- C2H6 |
C2H6 will last longuer since it has 18 energy bonds. It will only have a specific vibrational state that will induce separation which is harder to attain. O2 is easy to break. |
|
|
What are the 4 products in the atmosphere that are following a Lindemann-Hindshelwood mechanism? |
O2 C2H6 O3 HNO3 |
|
|
If you do not know the elementary steps to a reaction, How do you derive a rate law? |
You must find the rate laws empirically. (fitting) the values can be 0, interger or a fraction. |
|
|
What is the law of conservation of mass in terms of kinetics? |
It essentially that the rates of production of one compound will be equivalent to the rates of the reactants decomposition |
|
|
What is the law of mass conservation paradox? |
If you evaluates the rates of given reaction using the law of mass conservation, you will see a difference of the two rates by a factor of 2 |
|
|
typically photons are involved in most reactions in the atmosphere. Why are they not included in the kinetics? |
The concentration of photons will matter but it does not change over time. This hence result in a constant variable and is not affected. |
