revision

Question 1

role of salt bridge

Answer 1

1| allows for flow of ions bw 2 half cells

2| maintain electrical neutrality of cell

Question 2

role of electrolyte

Answer 2

source of ions which are used to allow flow of electric charge within cell (cations to cathode, anions to anode)

Question 3

define battery life

Answer 3

no. of charge/discharge cycles before a battery becomes unusable

Question 4

factors affecting battery life

Answer 4

1| increase temp, increase ROR of side reactions

2| dec. temp CAPACITY of battery dec. bc reaction rate dec. -> meaning cell discharge rate decreases and so does electricity that can be generated

3| reactants and products of cell become detached from electrode

4| react. and prod. may be converted to inactive forms via side reations

5| corrosion of internal components could inhibit cell reactions

Question 5

1ppm

Answer 5

1mg/L

Question 6

festures of optical isomers/enantiomers

Answer 6

chiral carbon + non superimposable mirror images

Question 7

define structural isomers

Answer 7

same molecular formula but different arrangement of atoms

Question 8

define steriosimers

Answer 8

same order of atoms but different spatial orientations

Question 9

define positional (structural) isomers

Answer 9

different positions of same functional groups

Question 10

define functional group (structural) isomers

Answer 10

different position of atoms give a different functional group
eg, propanal vs propanone

Question 11

define chain (structural) isomers

Answer 11

atoms arranged into branches/side chains

Question 12

describe process of mass sepc.

Answer 12

sample converted to gas(vaporised) -> ionised -> accelerated -> deflected -> detected

molecules are bombarded with electrons to make compound +ve (only positively charged particles are measured)

Question 13

IR type of energy level transitions

+ principle

Answer 13

vibrations of bonds in molecules/atoms -> make bonds bend and stretch

• IR measures the vibrations of atoms in a molecule and can give information about the type of bonds
  (functional groups) present in a molecule.
• IR involves the absorption of infrared radiation the wavenumber of which alters with different bond
  type

Question 14

competing equilibrium: CO poisoning equations

Answer 14

Hb4(aq) + 4O2(g) -> Hb4(02)4(aq) K1

Hb4(aq) + 4CO2(g) -> Hb4(CO)4 K2

Question 15

explain competing equilibrium: CO poisoning

Answer 15

Hb4(aq) + 4O2(g) -> Hb4(02)4(aq) K1

Hb4(aq) + 4O2(g) -> Hb4(CO)4 K2

K2&raquo_space;> K1, K value of reaction 2 is greater than reaction 1 so will be more preferentially binded to haemogoblin than O2 -> increase heam./CO complexes -> reduction in O2 carrying capacity

Question 16

explain how to treat CO poisoning

Answer 16

Hb4(aq) + 4O2(g) -> Hb4(02)4(aq) K1

Hb4(aq) + 4O2(g) -> Hb4(CO)4 K2

supply high concentration of O2 via an oxygen mask, which forces binding of 02 to haem. -> decrease haem. -> K2 reaction favours back reaction to increase Haem. Whilst dissociating haem./CO complexes -> CO is breathed out

Question 17

how does Vitamin C act as an antioxidant

Answer 17

by donating an electron from its OH groups to free radicals, allowing it to be preferentially oxidised over the triglyceride

Question 18

conditions for alkene -> alcohol
1. catalyst
2. reagent

Answer 18

1. H3PO4 catalyst and 300 degreesC
2. H20 (g)

Question 19

list the types of intermolecular bonding

Answer 19

dispersion, dipole-dipole, hydrogen

Question 20

list the types of intramolecular bonding

Answer 20

ionic, covalent, metallic

Question 21

how is the shape of an enzyme determined

Answer 21

its tertiary structure that is driven by the side chains (R-groups) of amino acids
eg. H-bonds/Dipole-dipole/ionic interactions/covalent cross links/dispersion forces

Question 22

conditions for hydrogenation of alkene (-> alkane)

Answer 22

H2

Ni catalyst and 150 degreesC

Question 23

functional group priority

Answer 23

carboxylic acid
ester
amide
aldehyde
keytone
alcohol
amine
alkene
alkyne
alkane
haloalkane

Question 24

H3PO4 catalyst and 300 degreesC
H20 (g)

Answer 24

conditions for alkene -> alcohol

Question 25

H2

Ni catalyst and 150 degreesC

Answer 25

conditions for hydrogenation of alkene (-> alkane)

Question 26

coenzymes

Answer 26

organic molecules that bind to the
active site of an enzyme during catalysis, thereby changing the surface shape and hence the binding properties
of the active site to enable function as intermediate carriers of electrons and/or groups of atoms

Question 27

induced fit model

Answer 27

In the induced fit model, the shape of the active site adjusts to
accommodate the shape of the substrate. This will require some
adjustment in the tertiary structure of the enzyme. Once the substrate detaches from the enzyme, the active site will return to its original shape

Question 28

function of a membrane in rechargeable cell (eg. zinc-cerium )

Answer 28

• to prevent the oxidant and reductant from coming into direct contact
• to prevent a spontaneous redox reaction occurring when the reductant and oxidant come into
  contact with each other
• to separate the two half-cells
• to prevent the excessive release of thermal energy in the cell.
• transport ions bw electrodes

Question 29

explain the presence of the small peak following parent ion peak

Answer 29

could be due to the presence of a one-unit heavier isotope such as 13C,
2H

Question 30

flashpoint

Answer 30

the lowest temperature at which the liquid forms sufficient vapour to ignite when an ignition source is present

Question 31

Lead acid battery, 1/2 Equ. anode

Answer 31

Pb(s) + H2SO4(aq) -> PbSO4(s) + 2H+(aq) + 2e-

Question 32

Lead acid battery, 1/2 Equ. cathode

Answer 32

2e- + 2H+(aq) + PbO2(s) + H2SO4(aq) -> PbSO4(s) + 2H2O(l)

Question 33

principle of NMR

Answer 33

radio waves/nuclear spin state makes nucleus flip in an applied magnetic field

• 1H NMR measures the change in the spin state of nuclei and can give information about the H
  environment present in the molecule.
• 1H NMR involves the absorption of radio waves, the chemical shift alters with the neighbouring
  environment.
• Neighbouring hydrogens will induce a splitting in the peak of a hydrogen atom leading to the ‘n+1’ rule.
  The peak area can indicate the number of hydrogens in the environment.

Question 34

increase temp, exothermic value of Kc ->

Answer 34

Kc decreases

Question 35

increase temp, endothermic value of Kc ->

Answer 35

Kc increases

Question 36

sources of methane

Answer 36

coal seem gas

biogas

Question 37

vitamin

Answer 37

organic substance that provides atoms/groups of atoms to support bodily functions