Kinetics and Equilibrium Flashcards
(50 cards)
1
Q
kinetics
A
- how reactions take place and how fast they occur
2
Q
reaction coordinate
A
- reactants
- products
- intermediates
- steps
- transition state
3
Q
reaction rate
A
- rate law
- experimental data
- change in concentration/time
4
Q
in order for a reaction to occur
A
- the reactants must collide
- with the proper orientation
- with a minimum energy (activation energy)
5
Q
what is the middle hump in a reaction coordinate?
A
- intermediate
- thermodynamic quantity
6
Q
- what are the two humps in a reaction coordinate?
A
- transition states
- kinetic quantities
7
Q
catalyst
A
- not used up in the reaction
- regenerates itself
- does not affect intermediate
8
Q
rate limiting step
A
- highest peak or slowest slep
9
Q
reaction rate formula
A
rate = -1/r (Δ[R]/Δt) = +1/p (Δ[P]/Δt)
r=reactant
p=product
- rate reactants used up
- rate products formed.
10
Q
rules for rate laws
A
- only uses reactants
- reverse reaction not considered
- no pure solids or pure liquids
- n1 +n2 + n3 = reaction order
11
Q
rate constant
A
- proportional to the probability that a collision will result in a successful reaction
k=Ae^(-E_a/RT)
- indirectly proportional to activation energy
- directly proportional to temp and A
- NOT AFFECTED by concentration of reactants.
12
Q
equilibrium
A
- achieved when forward rate = reverse rate
- does NOT tell us reaction rate
- reaction has not stopped
- THERMO not kinetic
13
Q
equilibrium constant
A
- ratio of equilibrium product and reactant concentrations
Keq = [product]^P/[reactants}^R
14
Q
equilibrium rules
A
- concentration of each species is in equilibrium
- constant ratio of products to reactants at a given temp
- no pure solids and liquids
- all capital K calculated the same way
15
Q
K>1
A
- in equilibrium favoring products
16
Q
K=1
A
- in equilibrium favors neither
17
Q
K<1
A
- in equilibrium favoring reactants
18
Q
reaction quotient
A
- Q
- concentrations when reaction is not at equilibrium
- value calculated using initial concentrations
- depends on temperature and concentration
19
Q
Q>K
A
- NOT in equilibrium
- reaction runs in reverse
- excess of product
20
Q
Q=K
A
- in equilibrium
21
Q
Q
A
- NOT in equilibrium
- reaction runs forward
- excess of reactant
22
Q
Free energy and reaction quotient
A
ΔG = ΔG^o + RTlnQ
23
Q
Free energy and equilibrium constant
A
ΔG^o = -RT*lnKeq
24
Q
LeChatelier Principle
A
- a system in equilibrium when stressed will shift in order to minimize that stress
25
add a catalyst how does the reaction change?
- it does not!
26
volume effects
- changing pressure stresses an equilibrium if the number of moles of gas changes in the reaction
27
increase pressure by decreasing volume
- shift to side with less moles of gas
28
decrease pressure by increasing volume
- shift to side with more moles of gas
29
if a reaction is endothermic
- treat heat as a reactant
30
if a reaction is exothermic
- treat heat as a product
31
respiratory equation
H2O + CO2 = H+ + CO3 2-
32
hyperventilating (increasing respiratory rate)
- expel a ton of CO2
- reaction runs to the left
- use up more H+
- blood becomes more alkalotic
33
decreasing respiratory rate
- hold onto more CO2
- reaction runs to the right
- produce more H+
- blood becomes more acidotic
34
formation equilibria
- equilibrium of a coordination complex is a formation constant
- reversing an equilibrium inverts the equilibrium constant
- combining multiple equilibria results in the multiplication of the equilibrium constants
35
solubility product
Ksp = [Sa+][Lt+]
36
How to predict precipitation?
Compare Qsp to K
37
Qsp>Ksp
- not in equilibrium
- you want to decrease the numerator so decrease the products
- therefore run reaction in reverse and solid salt will precipitate
- saturated
38
Qsp=Ksp
- in equilibrium
- saturated
- no more solute can dissolve
39
Qsp < Ksp
- not in equilibrium
- you want to increase the numerator so increase the number of products
- therefore run reaction in forward direction so more salt dissolves
- unsatured
40
common ion effect
- a salt's solubility will decrease if it is added to a solution containing a common ion
- a salt's solubility will increase if it is added to a solution containing something that removes a common ion
41
Dissociation constant
k2/k1=[A][B]/[AB]=Kd
42
Affinity constant
- the strength of binding of a molecule to ligand.
| k2/k1=[A][B]/[AB]=Kaff
43
Relate Kaff to Kd
Kaff=1/Kd
44
kinetics terms
- rate
- mechanism
- catalyst
- intermediate
- transition state
- activation energy
45
thermodynamics terms
- stability
- equilibrium
- spontaneity
- energy
- entropy
- enthalpy
- free energy
46
only thing that affects both kinetics and thermodynamics
- temperature
47
transition states
- non isolatable species
48
intermediate
- generated and used it
| - detectable and isolatable
49
raw law determined by
- rate determining step
50
what doesn't affect position of the equilibrium
- solids and liquids
| - inert gases
