Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem Y1 > Kinetics > Flashcards

Kinetics Flashcards

1
Q

Reaction rate is

A

Always positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Elementary reaction

A

Single step reactions
occur atatomic level
where order is = to molecularity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How to decide the order

A

The relationship between the values
If there’s no increase in rate with conc change it’s 0
If it’s proportional 1
If it like x4 then it’s 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

typical units for liquids/solutions for reaction rate

A

moldm-3s-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the problems with initial rate experiments

A

often inaccurate
wasteful - using loads resources to ignore more of the data
old fashion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in a half life experiment

A

determine the half life from the data by discovering how long it takes the rate to half
the greater the gradient the higher the k value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

inform me of the integrated rates laws for first order reactions

A

the k constant is found out by putting the reaction into the form the reaction = k x concentration of reactant to the power of the order of that reaction = d[A]/dt.
d[A]/dt is negative if the [A] is a reactant.
this is then rearranged to move all the [A] relating factors together
then intergrated
Try to put this into a linearized form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

first order reaction integrated laws put in nicer form

A

[A]t = [A]0e to the power of -kt
this is because for 1st order [A] follows an exponential decay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how can the k constat be found using the half life method

A

[A]t = [A]0 e^-kt
rearranged to form k = ln(2)/t (at time 1/2)
or t at half life point = ln(2)/k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

rate law equation for second rate reactions

A

-d[A]/dt = 2k[A]^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

linearised integrated form of 2nd rate reaction

A

1/[A]t = 2kt + 1/[A]0
indicates second order as gradient is timed by 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is a common problem with second order reaction

A

in cases where there are 2 reactants if [A] is not equal [B] difficult to interpret
to conteract this keep one reactants concentration constant by using a large excess of the unwanted reactant so its effectively constant
this makes its pseudo first order
therefore in the rate equation you can equate that reagent to Keff in which its K x the conc of that reagent
After obtaining the Keff value that then be then divided by the conc of that reactant to get the k value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are typical units for a second rate reaction

A

dm3mol-1s-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

2nd order half life equation

A

t1/2 = 1/2k[A]0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

0th order half life equation

A

t1/2 = [A]0/2k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a lifetime in kinetics

A

time to reach 1/e of initial rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

lifetime equation of 1st order

A

t = 1/k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

lifetime equation of 2nd order

A

r = e-1 /2k[A]0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

lifetime equation of 0th order

A

t = [A]0/k x e-1/e

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the Arrhenius equation

A

k = Ae to power of -Ea/RT

21
Q

linearised form of arrhenius equation

A

lnK = lnA - Ea/RT
where the gradient is -Ea/R

22
Q

How do you know if a plot is arrhenius like

A

if the plot of lnK vs 1/T is linear

23
Q

How to handle complex reactions

A

isolate them and basically complete pseudo first order reactions separately for each variable

24
Q

what is the portor’s flash photolysis experiment used for

A

studying of fast reactions
1. premix excess reactant (B) and precursor (A2)
2. radicals (A radical ) genrated in flash

25
Q

what is the rate determining step

A

the slowest past of the reaction that dictates how quickly final product is made

26
Q

how to make steady state approximation equation

A

d( Whatevers being measured) / dt = rate of production - rate of loss

27
Q

what is a catalyst

A

decreases the activation energy of a reaction

28
Q

What is carbonic anhydrase essencial in

A

enabaling organisms to maintain acid base balance and transport carbon dioxide

29
Q

what is an enzyme assay

A

any lab test measures enzyme activity

30
Q

assumptions of the michaelis menten equation

A

the binding of the enzyme and the substrate is fast and reversible
the ES complexslowly breaks down actig as the rate determining step

31
Q

how is velocity distinguished in michaelis menten equation

A

velocity = kcat[ES]

32
Q

Assumptions about substrate concentration

A

the concentration of product can be neglected compared to that of substrate. (always true in the initial stages)
the concentration of substrate is in large excess in comparison to the enzyme

33
Q

based on substrate assumptions what is suggested about the substrate concetration initially

A

[S]0 = [S]free

34
Q

equation for Km

A

Km = (K-1 + Kcat)/K1

35
Q

what is Vmax and how is it calculated

A

Vmax is maximum velocity when all enzyme molecules are bound to substrate
Vmax = Kcat x [E]total

36
Q

What is michaelis menten equation

A

v = Vmax[S] / Km + [S]

37
Q

what are the units Kcat

A

s-1

38
Q

What Kcat and what is the equation

A

the maximum number of substrate converted to products per active site per unit time when the enzyme is saturated with substrate
Kcat = Vmax / [E] total

39
Q

What is Km and the equation for it

A

concentration at which the reaction is half the maximum reaction velocity
Km = Vmax / 2

40
Q

What is the specificity constant and how is it measured

A

optimul substrate for an enzyme
specificity constant = Kcat/ Km

41
Q

What does collision theory assume

A

perfect gas behavious modelled on hard spheres of negligable volume with no long range interactions

42
Q

What is Kcoll and the equation to calculate it

A

Kcoll is the collisional rate coefficient
Kcoll = sigmaAB root (8KbT)/pi microAB

43
Q

What is sigma AB

A

collisional cross section
pi (radius A + radius b) ^2

44
Q

what mu AB

A

how massive in kg a collison pair is using atomic mass
Ma x Mb / Ma + Mb

45
Q

What is the general Kcoll value at T = 298K

A

2 x 10^-10

45
Q

how to calculate reaction time from discharge flow technique

A

T = distance to detector(m)/ gas flow velocity (m/s)

46
Q

In what scenario can A be linked with Kcoll

A

bimolecular reactions

47
Q

What can the A in the arrhenius equation stand for in the case of gas phase kinetics

A

A= Kcoll x p (steric factor)

48
Q
A

Biochem Y1 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions