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Question 1

how do we solve rate equations numerically

Answer 1

we get given a reaction mechanism // operations

and we need to set up differential mechanisms to describe the change in conc for each of the elements in that mechanism

we look at every element in all the mechanisms

and we write a differential equation for each one where we include what forms and what destroys it!!

like we normally do

and then we can solve these using diff methods to tell us the slope of the change of conc at a particular time / point

knowing where the slope is helps us predict where the next point is going to be

Question 2

when u write differential equations,, when do u need to put 2K1 or a larger number in front of the k

Answer 2

u add a 2 in front of the k when u form 2 of that thing following the arrow.

aka if we’re writing an equation for NO and the formation of it is 2NO and ur going from N2O2 to 2NO

the k ,, aka rate constant will be 2k bc ur making 2 of them

aka the rate is 2 times faster
so we add a 2 to say this

Question 3

eulers method is what

Answer 3

when u use the equations to tell u the slope of the change of conc at a particular point

and knowing where the slops is will help us predict where the next point is going to be.

Question 4

describe the graph for eulers method

Answer 4

u have conc of the reactant on the y axis

u have time on the x axis

u then have a curve
u obvs know the [NO]o and the [N2O2]o so u just guess what the k values are

and this will give u a slope and the gap between t zero and t of the end of the slop is called h

and then u predict what the [NO] is at the point h

then u use this to predict rate of [N2O2] to predict [N2O2].

then u just keep predicting the slope at diff times

and obvs the slopes we make are not exactly the slop we have

but we keep altering the values until we match that slope

Question 5

whats the runge kutta 4th order

Answer 5

its easily programmed for small sets of equations

it helps us solve the differential equations

by taking lots of small recordings,, make sure the h is super small bc the smaller h is,, the more accurate ur predictions are.

Question 6

whats is the principle of reversability

Answer 6

at equilibrium, each individual step in a mechanism is also at equilibrium

so the forward reaction follows the same path as the backward one

u go from A to B to P and the back reaction is the same as the forward one,, meaning if the forward one is hard to measure,, we can measure the backward one.

this is what u do for menthol synthesis

Question 7

whats an enzyme

Answer 7

a biological molecule that acts like a catalyst

it lowers the activation energy barrier

its very specific meaning it only catalyses specific reactions

Question 8

michaelis menton mechanism : enzyme reaction ,, describe it

Answer 8

E + S <—> ES —> E + Z

E = enzyme
S = substrate
ES = enzyme substrate complex

E = enzyme
Z = product

Question 9

whats [E]o

Answer 9

initial enzyme conc

Question 10

what do we apply to [E]o

Answer 10

we apply the steady state approx

to find the rate, v,

Question 11

whats the rate, v, equation for the michaelis reaction

Answer 11

v =
k2 [E]o [s] // (k-1 + k2 / k1) + [s]

= V[S] / km + [S]

where km is the michaelis constant

Question 12

whats V in the Michaelis simplified equation

Answer 12

V = k2[E]o

Question 13

when we have the michaelis equation type thing,,, what do we plot on a graph

Answer 13

Rate,, v on y axis

[S] on the x axis

and u get an ‘r’ type curve

Question 14

when we plot rate against [s] on the michaelis graph,, what is the top of the ‘r’ curve thing

Answer 14

that is the limiting rateeeee

aka the conc of substrate is so high that all the enzymes are used up meaning if u add any more substrate,, it doesnt change the rate at all,, bc all enzymes are used up duhhh.

Question 15

in the michaelis plot of rate on the y axis and [s] on the x axis,, what is the half the rate

Answer 15

v/2

Question 16

rate in the michaelic equation is whattt, and what does it mean when we have a large [s]

Answer 16

the rate equation is
V[s] / Km+[S]

is u have a larger [s] it means that Km is kinda irrelavent

meaning rate = V[s] / [s] and then u cancel out the [s] so rate = V

Question 17

V in terms of {e]o

Answer 17

V = [E]o K2

Question 18

when [s] = km,, what does this do to the v,, rate equation

Answer 18

rate = V[S] / 2[S]

and then we cancel the [s] out and we get

rate = V/2
so finding v/2 gives us the s value on the x axis where it equals to km

Question 19

to look at enzyme data what do we do

Answer 19

we look at the lineweaver burt plot

Question 20

axis on a lineweaver burt plot

Answer 20

mol-1 s aka 1/v on the y axis

1/[s] aka mol-1dm3 on the x axis

Question 21

in the lineweaver plot what is the slope of the line

Answer 21

slope of the line = km/m

aka the limiting rate

Question 22

name 3 types of chain reactions

Answer 22

polymerisation

combustion

explosions

Question 23

what does a chain recation involve

Answer 23

a chain reaction involves an intermediate that is regenerated so that a small amount produces a lot of product

Question 24

name the 3 types of eleentary steps a chain reaction usually has

Answer 24

initiation

progagation

termination

Question 25

whats initiation step in a chain reaction

Answer 25

gemerates the chain carrier

Question 26

whats propagaetion i na chain reaction

Answer 26

produces products and regeerates the chain carrier

Question 27

whats the termination step in a chain reaction

Answer 27

it destroys the chain carrier

Question 28

what 2 steps can a chain reaction have but isnt certain to have

Answer 28

inhibition step branching step

Question 29

describe what the inhibition step is in chain reaction

Answer 29

destroys product and slows the reatcion

Question 30

whats the braching step in a chain reaction

Answer 30

it creates more chain carriers than it destroys it can lead to explosions

Question 31

how can u tell a reaction equation is a initiation step

Answer 31

if ur going from 2 molecules to an excited state oneee the excited state is the chain carrier

Question 32

whats the initiatiopn step usually involving

Answer 32

it normally involves an inert body aka the wall of the chamber etccc we call this M

Question 33

when an excited state reaction with smt random to give another excited state what step do we call this

Answer 33

we call it the propagation step as it produces products (stabilises the excited state) and regenrates a chain carrier (makes the other part of what u used to neutralise the chain carrier to a diff chain carrier.) aka Br* + H2 ---> HBr + H*

Question 34

what step is it when we have H* + Br2 ---> HBr +Br*

Answer 34

we call this the propagation step

Question 35

when u have H* + HBr ---> H2 + Br* what do we call this

Answer 35

we call this the inhibition step bc ur destroying the HBr product ,, slowing the reaction.

Question 36

what is the termination stepp,,, aka what will the equation look like

Answer 36

u will have 2 excited states aka 2 chain carriers and theyre gonna turn into a neutral molecule. aka the chain carrier is gonna be destroyed.

Question 37

what is polymerisation an example of

Answer 37

its an example of a chain reaction

Question 38

what different types of polymerisation are there

Answer 38

theres step and chain polymerisation

Question 39

whats the diff between step and chain polymerisation: first explain step polymerisation

Answer 39

- chain growth forms between any 2 molecular species A-B + A-B --> A-BA-B A-BA-B + A-B --> A-BA-BA-B any 2 monomers or dimers or oligomers can react,, not just the chain ends

Question 40

whats the diff between step and chain polymerisation: aka whats chain polymerisation

Answer 40

it only occurs between a monomer and a growing chain. monomers are only added to the active chain end. A-BA-B + A-B --> A-BA-BA-B aka growth happens one monomer at a time. so u have a train and it keeps picking up carridges as it stops at stations