chem option

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/71

encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

72 Terms

1
New cards
calculating the efficiency of an energy transfer
Efficiency = (useful output energy / total input energy) × 100
2
New cards
energy density definition
the energy stored per unit volume
3
New cards
specific energy definition
the energy produced per unit mass
4
New cards
advantages of natural gas (4)

relatively clean

higher specific energy than coal and oil

can be compressed or liquefied for easy transport

does not contribute to acid deposition

5
New cards
disadvantages of natural gas (4)

non-renewable

produces CO2

lower energy density than coal and oil

unevenly distributed around the world

6
New cards
advantages of coal (4)

inexpensive

high specific heat capacity and energy density

can be converted into liquid fuels

distributed throughout the world

7
New cards
disadvantages of coal (4)

mining of coal can cause environmental damage

non-renewable

produces CO2

combustion wit sulfur produces acid deposition

8
New cards
advantages of crude oil/petroleum products (3)

inexpensive

high specific heat capacity and energy density

easily transported

9
New cards
disadvantages of crude oil/petroleum products (4)

non-renewable

produces CO2

drilling for and transportation of crude oil can cause environmental damage

unevenly distributed around the world

10
New cards
fractional distillation separation is based off of:
boiling points
11
New cards
what is assigned an octane number of 100
2,2,4-trimethylpentane
12
New cards
methods of increasing octane number:

catalytic reforming

unevenly distributed around the world

unevenly distributed around the world

cracking

13
New cards
what are aromatisation and isomerisation
the catalytic reforming of straight-chain hydrocarbons with low octane numbers into cyclic or branched chains
14
New cards
what is cracking
breaking long-chain hydrocarbons into short-chain hydrocarbons
15
New cards
what is coal gasification
the process of converting coal into synthetic natural gas (CH4)
16
New cards
write out the production of synthetic natural gas (coal gasification)

C(s) + H2O(g) → CO(g) + H2(g)

CO(g) + 3H2(g) → CH4(g) + H2O(g)

17
New cards
what is coal liquefaction
conversion of coal into liquid hydrocarbons
18
New cards
write out the production of coal liquefaction
nC(s) + (n+1)H2(g) → CnH2n+2(l)
19
New cards
define nuclear fusion

the process of lighter nuclei fusing together to form a heavier nucleus

binding energy per nucleon increases

20
New cards
define nuclear fission

the process of splitting a large unstable nucleus into smaller, more stable nuclei

binding energy per nucleon increases

21
New cards
define the critical mass
the minimum mass of a fuel for the reaction to be self-sustaining
22
New cards
what does a breeder reactor do
produces more fissile material than it consumes
23
New cards
what to do with low level waste
stored until isotopes decay and then disposed in landfill
24
New cards
what to do with intermediate level waste
bury in shallow repositories
25
New cards
what to do with high level waste
vitrification and storage deep underground in a geologically stable area
26
New cards
what is the definition of binding energy
the energy required to disassemble a nucleus into its component nucleons
27
New cards
seperate nucleons have a ___________ mass than the combined nucleus. the difference is known as the _____ __________

greater

mass defect

28
New cards
what units is the result of E=mc^2 in and how to convert to kJ.nucleon^-1

J.nucleus^-1

divide by 1000 and then the mass number

29
New cards
how to convert mass defect from amu to kg
multiply by 1 amu
30
New cards
in order for a gas to absorb IR radiation there must be:
a change in dipole moment of the molecule as the bonds undergo asymmetric stretching or bending
31
New cards
explain the greenhouse effect
short wavelength (UV/Vis) wavelength radiation from the sun reaches the surface of the earth, the earth reradiates this as longer wavelength (IR) which are absorbed by greenhouse gasses and reradiate it back to the surface of the earth
32
New cards
how does ocean acidification occur?

concentration of CO2 in aq and g is in equilibrium

CO2(g) ⇌ CO2(aq)

CO2 reacts with water to form carbonic acid which is a weak acid and dissociates, producing H+ ions

H2CO3(aq) ⇌ H+(aq) + HCO3-(aq)

CO2(aq) + H2O(l) ⇌ H2CO3(aq)

33
New cards
global dimming is caused by
increasing amount of particulates such as oxides of sulfur, ash and soot in the atmosphere that absorb incoming solar radiation
34
New cards
difference between primary and secondary cells
secondary cells are rechargable, the redox reactions that occur at the anode/cathode can be reversed using electricity
35
New cards
advantages and disadvantages of lead acid batteries (+1, -3)

+:simple to manufacture, cheap

-: low energy density, overcharging can lead to the production of hydrogen gas, lead is a toxic metal that can affect the CNS

36
New cards
advantages and disadvantages of nickel-cadmium batteries (+1, -1)

+: charge quickly and have high number of charge/discharge cycles

-: cadmium and nickel can have environmental concerns during disposal

37
New cards
advantages and disadvantages of lithium-ion batteries (+1, -2)

+: high energy density

-: expensive, can explode

38
New cards
lead acid battery: forward and reverse reactions anode/cathode/overall

FORWARD:

Anode: Pb + HSO4- → PbSO4 + H+ + 2e-

Cathode: PbO2 + HSO4- + 3H+ + 2e- → PbSO4 + 2H2O

Overall: Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

39
New cards
nickel cadmium battery: forward and reverse reactions anode/cathode/overall

FORWARD:

Anode: Cd + 2OH− → Cd(OH)2 + 2e−

Cathode: 2NiO(OH) + 2H2O + 2e− → 2Ni(OH)2 + 2OH−

Overall: Cd + 2NiO(OH) + 2H2O → 2Ni(OH)2 + Cd(OH)2

40
New cards
lithium-ion battery: forward and reverse reactions anode/cathode

FORWARD

Anode: Li (graphite) → Li+ (electrolyte) + e-

Cathode: Li+ (electrolyte) + e- + CoO2 (s) → LiCoO2 (s)

41
New cards
thermodynamic efficiency of a fuel cell equation
ΔG / ΔH × 100 %
42
New cards
how to find Q in the nerst equation
concentration at the anode / concentration at the cathode
43
New cards
what is the equation for photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
44
New cards
what part of a molecule is responsible for its ability to absorb visible light
conjugated system
45
New cards
fermentation of glucose reaction
C6H12O6 → 2C2H5OH + 2CO2
46
New cards
why can't vegetable oils be used in diesel engines
they are too viscous
47
New cards
advantages and disadvantages of biofuels (+3, -3)

+: high octane rating, renewable, produces less CO

-: lower specific energy than octane, more volatile and therefore evaporates easily, could otherwise be used for food production

48
New cards
general equation for transesterification of an ester and an alcohol
RCOOR1 + R2OH → R1OH + RCOOR2
49
New cards
proton exchange membrane fuel cell: reactions at anode/cathode

Anode: 2H2 → 4H+ + 4e-

Cathode: O2 + 4H+ + 4e- → 2H2O

50
New cards
alkaline fuel cell: reactions at anode/cathode

Anode: 2H2 + 4OH- → 4H2O + 4e-

Cathode: 2H2O + O2 + 4e- → 4OH-

51
New cards
direct methanol fuel cell: reactions at anode/cathode

Anode: CH3OH + H2O → CO2 + 6H+ + 6e-

Cathode: 3/2O2 + 6H+ + 6e- → 3H2O

52
New cards
microbial fuel cell: reactions at anode/cathode

Anode: CH3COO- + 2H2O → 2CO2 + 7H+ + 8e-

Cathode: 2O2 + 8H+ + 8e- → 4H2O

53
New cards
n type doping is
the addition of a group 15 element, adding an extra electron
54
New cards
p type doping is
the addition of a group 13 element, creating a hole
55
New cards
DSSC iodine oxidation and reduction

Oxidation: 3I− → I3− + 2e−

Reduction: I3− + 2e− → 3I−

56
New cards
a large conjugated system absorbs ________ wavelengths of light
longer
57
New cards
identify a reagent and a catalyst for a transesterification reaction

reagent: methanol/ethanol

catalyst: strong acid/base

ie. HCl/NaOH

58
New cards
why are DSSC so efficient (2)

large surface area

dye converts almost all absorbed photons into electrons

59
New cards
how to go from J to MJ
divide by 1000 then by 1000 again
60
New cards
in concentration cell, the lower concentration will be the
anode
61
New cards
mass defect =c
mass of nucleons - mass of nucleus
62
New cards
the mass of a nucleus can be found by mutiplying the number of _________ by the ________

nucleons amu

63
New cards
E is in
J/nucleus
64
New cards
convert J/nucleus to kj.mol-1
divide by 1000 and multiply by avogadro constant
65
New cards
convert J/nucleus to kJ.nucleon
divide by number of nucleons and then divide by 1000
66
New cards
difference in bonding between UO2 and UF6
UO2 is a crystalline ionic solic (high melting point)
67
New cards
UF6 is a covalent structure - non polar
68
New cards
increasing the T of a metal does what to electrical conductivity
decreases as metal ions vibrate
69
New cards
what does n and p type doping actually do
increased electrical conductivity of the silicon lattice
70
New cards
explain the operation of a DSSC

dye has a conjugated system

dye absorbs a photon and injects an electron into TiO2

electrons transferred to semiconductor

dye takes electron from electrolyte (dye is oxidised)

electron flows through external circuit

71
New cards
types of isotope separation

centrifugation (heavier 238 forced to the outside while lighter 235 stays on the inside)

gaseous diffusion (pass through porous membrane)

72
New cards
how to concentrate U235
convert to UF6 with lower boiling point and then separate based off of molar masses