first part

Question 1

types of bond breaking

Answer 1

heterolytic
homolytic

Question 2

heterolytic bond breaking

Answer 2

when both electrons in a covalent bond go to one species.

2e- chemistry
ions form

Question 3

homolytic bond breaking

Answer 3

when one electron goes to each species
1e- chemistry
radicals are formed

Question 4

what is bond dissociation enthalpy

Answer 4

energy required to break a bond homolytically

the radical one

Question 5

what does a high bde mean

Answer 5

its a strong bond
needs lots of energy to break it
poorly stabilised radicals

(lots of energy is needed bc the radicals dont want to be formed bc they will be poorly stabilised) 9hydrogen radical, methyl radical)

Question 6

what does a low bde mean

Answer 6

little energy needed to break the bond homolytically
weak bond
well stabilised radicals ( tertiary structures, strong electrophilic radicals)

Question 7

what is enthalpy change

Answer 7

heat given in or taken out by a reaction

we can estimate this using the bde values

Question 8

breaking bonds require

Answer 8

energy
positive numbers

Question 9

forming bonds dont require

Answer 9

energy
negative numbers

Question 10

negative enthalpy value means the reaction is

Answer 10

exothermic

Question 11

positive enthalpy value means the reaction is

Answer 11

endothermic

Question 12

what is S

Answer 12

change in enthalpy
likes disorder
gas> solid
2 molecules>1 molecule.
higher S = higher entropy
snake in a tree
snakes like being in the leaves bc its more disordered than the trunk. larger s is more disordered as the leaves are higher off the ground than the bark

Question 13

gibbs free energy equation

Answer 13

change in cG = cH -Tcs
kJmol-1 = kJmol-1 - K JK-1mol-1

Question 14

what is an exergonic reaction

Answer 14

reaction where the products have less energy than the starting material

products are favoured at equilibrium

looks like exothermic reaction profile

Question 15

what is an endergonic reaction

Answer 15

where the starting materials have lower energy than the products

starting materials are favoured at equilibrium

looks like endothermic reaction profile

Question 16

in the endergonic and exergonic reaction profiles, what is the gibbs energy

Answer 16

height difference between the 2 lines of sm to p

Question 17

if G has a negative value,

Answer 17

its an exergonic reaction
products are favoured

Question 18

if G has a positive value,

Answer 18

its an endergonic reaction
sm are favoured

Question 19

equilibrium constant equation

Answer 19

conc of products / conc of reactants

Question 20

another change in gibbs equation kJmol-1

Answer 20

(- gas constant x temp) x ln(equilibrium constant)

Question 21

what does the value of gibbs free energy tell us

Answer 21

if sm or p are favoured at equilibrium

doesnt tell us about the rate.

Question 22

rate equation with differentials,, yk this girl!!

Answer 22

d(conc products)/d(time)

change in product conc/ change in time

Question 23

what is a rate equation eg

Answer 23

k [a] [b]

Question 24

[a] to the power of 1 means

Answer 24

first order
sn1
change of this is proportional to change in rate

Question 25

[a] to the power of 2 means

Answer 25

second order sn2 change of this is proportional to double the change in rate

Question 26

what relates the rate constant and the activation energy

Answer 26

arrhenius equation k = Ae ^ -Ea/Rt

Question 27

what is at the top of an energy curve

Answer 27

local maxima peaks transition states higher in enery less stable

Question 28

what is a transition state

Answer 28

occurs during bond making / breaking dotted arrow diagram at local maxima peaks higher in energy cant be observed or isolated transient species (not around for a long time)

Question 29

what is on the slightly lower parts of an energy curve diagram

Answer 29

intermediates occur at local energy minima

Question 30

what is an intermediate

Answer 30

carbocation intermediate can be observed and isolated lower in enery, more stable bonds arent in the process of being formed or broken (no dotted lines but a + or -) sn1

Question 31

what does it mean to be a transient species

Answer 31

to not be around for a long time

Question 32

how can a transition state be drawn

Answer 32

dotted line square brackets = sign with | in the middle in top right hand corner of the [ ]

Question 33

what is the hammond postulate

Answer 33

shows if the transition state is closer to the starting materials or the products

Question 34

hammond postulate for an exergonic reaction

Answer 34

Ts resembles starting materials as that line is closer to the local energy maxima peak.

Question 35

hammond postulate for endergonic reactions

Answer 35

Ts resembles products as the line for products is closer to the local energy maxima