Kinetics

Question 1

an average rate is defined over

Answer 1

some time window

Question 2

RATE =

Answer 2

change in concentration / change in time

Question 3

Mole rates are related. what is the relationship like

Answer 3

they are porportionate. balanced equation will increase moles proportionally

Question 4

Rates can change, how?

Answer 4

The rate of production can increase or decrease, check slope steepness. If slope is steep, rate is fast. If slope less steep, rate slowed down.

Question 5

Rate law

Answer 5

equation showing how reaction rate depends on concentration of each reactant

Question 6

if aA+bB –> cC + dD, rate =

Answer 6

k [A]^m [B} ^n

k = rate constant
m = reaction order in A
n = reaction order in B

Question 7

reaction rate describes

Answer 7

how fast reaction is going

Question 8

rate laws

Answer 8

show how the reate depedns on the reactant concentrations

Question 9

half-life

Answer 9

time it takes to react 50%

Question 10

arrhenius equation describes

Answer 10

how rate constant changes with TEMPERATURE

Question 11

Reaction mechanisms

Answer 11

-connect microscopic molecular processes to overall rate
-reveal how reaction occurs

Question 12

Intergrated rate laws describe

Answer 12

mathematical functions give concentrations through time

Question 13

Method of initial rates: granular

Answer 13

• Two expirments vary
• divide inital [B] values with ^n to get n ( rate3/rate2 = [B3}^n / [B2] ^n]
• divide inital [A] values with ^m to get m (9 = 3 ^m)
• use data on any one expiriment and plug in for according rate law

Question 14

rate laws:
rate = k[A]⁰ = k
rate = k[A]
rate = k[A][B]
rate = k[A]²[B]

Answer 14

Order and units:
0. M/s
1. 1/s
2. 1/(M s)
3. 1/m^2 s)

Question 15

Zero Order Integrated law

Answer 15

[A]t = -kt + [A]₀

[A]₀ is inital conc.
[A]ₜ is concentration at t

STEEP linearly DECREASE slope

Question 16

half life zero order

Answer 16

t₀.₅ = [A]₀ / 2k

Question 17

First order intergraded

Answer 17

[A]ₜ = [A]₀e⁻ᵏᵗ
or
ln [A]ₜ/[A]₀ = -kt

-linearly decrease slope

Question 18

Second order integrated

Answer 18

1/[A]ₜ = kt + 1/[A]₀

[A]₀ = initial conc
[A]ₜ = conc at time

-linear INCREASE slope

Question 19

half life first order

Answer 19

t₀.₅ = ln(2)/k

Question 20

half life second order

Answer 20

t₀.₅ = 1/k[A]₀

Question 21

conc vs time zero

Answer 21

straight down then flat

Question 22

conc vs time first

Answer 22

smooth curve down

Question 23

conc vs time second

Answer 23

broken curve down

Question 24

Elemtary reaction

Answer 24

individual molecular event

Question 25

overall reaction

Answer 25

reaction stoichiometry

Question 26

reaction intermediate

Answer 26

species formed in one step and consumed in another

Question 27

catalyst

Answer 27

if consumed in first then regenerated

Question 28

ther rate law for an elementary reaction only follows directly from its molecularity because

Answer 28

An elementary reaction is an individual molecular collision

Question 29

determine fast step and slow step

Answer 29

- fast is at equilibrium - slow is not

Question 30

net reaction

Answer 30

add all elements that cant be cancelled up

Question 31

collisions happen all the time but only some causes _____________________

Answer 31

an event to happen

Question 32

reactants must ______ with correct _________

Answer 32

collide, orientation

Question 33

- 0 < p ≤ 1 YUP - p for simple molecules: - p for large molecules: - IF reaction isnt sensitive to orientation

Answer 33

P for simple: 0.001-1 P for large: < 10⁻⁵ not sensitive: p = 1

Question 34

Collision theory: For a biomolecular reaction to take place, reactants A and B must _______ with __________ __________, and an energy greater than the _______ ________

Answer 34

collide, proper orientation, activation energy

Question 35

in collision theory, rate = k[A][B] --> k = Zpf where Zpf means

Answer 35

Z = volumetric collision freq (INCREASES with T) p = fraction with correct orientation (NO CHANGE with T) f = fraction with sufficient energy (INCREASES with T)

Question 36

Transition State: The ________ _____ of atoms that are ________________ along the pathway from reactants to products

Answer 36

Unstable group, highest energy

Question 37

Activation energy

Answer 37

Minimum energy reauired for successful reaction

Question 38

As T ________, fractions of collisions with _________ ________ react to increases exponentially.

Answer 38

Increases, sufficient energy

Question 39

As T increases, fractions of collisions with sufficient energy react to increases exponentially. Higher T -->

Answer 39

BIGGER SPIKE on graph at beggining, ends up lower --> smaller Ea --> LARGER eˣ --> LArger reciprocal ---> larger f & k --> increased rate

Question 40

Arrhenious equation

Answer 40

k = Ae⁻ᴱᵃ/ᴿᵗ or lnk = -Ea/R (1/T) + lnA

Question 41

Arrhenius plot faciliates graphical determination of the ________ ______ ( which is the slope)

Answer 41

activation energy (lnk vs 1/T)

Question 42

what order reaction are enzymes at low substrate concentration and high substrate concentration

Answer 42

LOW: First-order behaviour - rate increases linearly with S HIGH: Zeroth-order, once all enzyme is complexed, rate of reaction saturates.