IB Chemistry SL Option C
efficiency
(useful output energy/total input energy) x 100
fermentation
37°C, anaerobic conditions, glucose and a yeast catalyst to produce ethanol
gasohol
90% gasoline and 10% ethanol from fermentation higher octane number than gasoline
coal
Advantage: relatively inexpensive Disadvantage: finite, produces CO2(greenhouse gas) when burned
petroleum
Advantages: ease of transport Disadvantages: produces CO2 when burned
natural gas
Advantages: relatively clean fuel Disadvantages: produces CO2 when burned
Coal liquefaction conditions
Hydrogen gas, 450°C and high pressure
fuel
a substance that provides energy as the result of a chemical change or nuclear reaction
chlorophyll
absorbs wavelengths of visible light from 430-660 nm
greenhouse gases
allow the passage of incoming solar short wavelength radiation but absorb the longer wavelength radiation from the Earth and re-radiate it back to the earth
positron
antiparticle of an electron; positively charged beta particle
C atoms increases
boiling point increases
global warming
caused by greenhouse gases such as carbon dioxide and methane
non-renewable resources
coal, petroleum, natural gas
fossil fuels
compounds that contain C,H,N,S&F
car engines
compression ignition
catalytic reforming
converts low octane short-chain hydrocarbons into high-octane aromatic hydrocarbons (used to increase octane rating)
Isomerisation
converts low octane short-chain hydrocarbons into high-octane branched hydrocarbons using a platinum and zeolite catalyst
fractional distillation
crude oil is separated depending on the boiling points of the different fractions
global dimming
decreasing amounts of solar radiation reaching the surface of the earth as particulate matter reflects the solar radiation before it reaches the earth
beta positive decay (forms a positron)
electron capture, mass number doesn't change and the atomic number decreases by one
beta minus decay (forms an electron)
electron emission, mass number doesn't change and the atomic number increases by one
First Law of Thermodynamics
energy is neither created nor destroyed, but may be converted from one form to another
specific energy
energy released from fuel/mass of fuel consumed
energy density
energy released from fuel/volume of fuel consumed
degraded energy
energy that is no longer able to do work
biofuels
fuels who's energy is obtained from biological carbon fixation
straight chain hydrocarbons
greater tendency to auto-ignite and cause knocking
biological pigments
have conjugating systems (alternating single and double bonds)
ocean acidification
heterogeneous equilibrium between concentrations of aqueous carbon dioxide in the oceans and gaseous carbon dioxide in the atmosphere
gamma decay
high energy electromagnetic emission, mass number and atomic number do not change
higher carbon content
higher specific energy
renewable resources
hydroelectricity, biomass
Nuclear fission process
large unstable nuclei collide with a neutron and break down into smaller stable nuclei releasing energy forming a self-sustaining chain reaction
photosynthesis
light energy is converted into chemical energy and is endothermic
Nuclear fusion process
lighter nuclei fuse to form heavier nuclei releasing energy fusion of deuterium and tritium (isotopes of hydrogen) provide the Sun's energy forming helium and a neutron
cracking
longer chain hydrocarbons being broken it up into shorter chain hydrocarbons
Nuclear power stations
low greenhouse gas emission but produce nuclear waste
Benefits of coal gasification
lower sulfur oxide, nitrogen oxide and particulate emissions compared to burning coal
alpha decay
mass number decreases by four and the atomic number decreases by two
octane number
measure of a fuel's ability to resist knocking in a car engine higher the octane number, the higher the resistance and the less knocking
volume
molar mass/ density
higher energy density
more energy stored or transported
MON
motor octane number
heptane
octane number 0 straight-chain hydrocarbon so has a lower octane number
iso-octane
octane number of 100 branched hydrocarbon so has a higher octane number
Nuclear fusion
potential to provide almost unlimited energy fuel is inexpensive and abundant and no radioactive waste is produced
auto-ignition
premature ignition which causes knocking causing the engine to lose power
Coal gasificaition
process of converting coal and steam into syngas which is a mixture of CO and Hydrogen gas
Coal liquefaction
process of converting coal into liquid hydrocarbons that can be used as fuels by hydrogenation
Nuclear weapons
produced by nuclear fusion and fission
RON
research octane number
octane number of 93
same tendency to auto-ignite as 93% iso-octane and 7% heptane
continuous spectrum
shows all the frequencies or wavelengths of visible light
particulate matter
sulfur dioxide, ash, soot and polluted water droplets in clouds
carbon fixation
takes inorganic carbon (carbon dioxide) and turns it into organic compounds
thermal cracking
temperature of approximately 750°C and at a pressure of 70atm high proportion of alkenes then polymerised to make plastics
energy
the ability to do work measured in joules
mass defect
the amount of mass that is converted into energy in a fission reaction calculated by E = mc²
binding energy
the energy required to disassemble an atomic nucleus into its component parts (nucleons) the higher the binding energy the more stable the nuclei
critical mass
the minimum amount of radioactive isotopes needed to produce a self-sustaining fission reaction
half-life
the time taken for a given sample to decay to one half of the mass of the original isotope
larger nuclei to the right of ⁵⁶Fe
undergo fission to increase the binding energy per nucleon to increase stability
smaller nuclei to the left of ⁵⁶Fe
undergo fusion to increase the binding energy per nucleon to increase stability
Nuclear fission
used to generate electricity in a nuclear power station
catalytic cracking
uses a zeolite catalyst that allows cracking to take place at a lower temperature 500°C and pressure high proportions of branched alkanes and aromatic hydrocarbons which burn more easily in car engines
transesterification
vegetable oils converted into a useable fuel triglyceride and alcohol with a strong base as a catalyst to form glycerol and an ester ester molecules have a lower viscosity so can be used as fuels in diesel engines
absorption line spectrum
when electrons absorb energy and transition from lower to higher energy levels
emission line spectrum
when electrons emit energy and transition from higher to lower energy levels
