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