Chemistry U3 AOS1

• Chemical substances have stored energy known as chemical potential energy
• Fuels are substances that have stored energy which can be released relatively easily as heat or power
• Chemical energy within fuels can be released as different forms of useful energy such as heat, light, sound
• Energy released by fuels is measured in SI units called joules
• Most of Australia's energy demand is met with the burning of fossil fuels, mostly coal
• Only 14% of Australia's current electricity comes from renewable energy sources
• Non-renewable resources cannot be replenished at the rate at which they are consumed
• Renewable resources can be replaced at the rate at which they are consumed
• Fossil fuels are a type of non-renewable resource
• Fossil fuels include coal, crude oil, and natural gas
• Fossil fuels are formed from ancient plants, animals, and microorganisms decomposing and being buried under high temperatures and pressures
• Fossil fuels retain some of the chemical energy produced through photosynthesis
• Fossil fuels are basically trapped solar energy
• Fossil fuels form over millions of years and cannot be readily replenished, making them non-renewable
• Wood turns into coal after being buried under mud and sand for millions of years
• Proportion of hydrogen and oxygen decreases, increasing the carbon percentage
• Wood becomes peat (60% C), brown coal (70% C), and black coal (90% C)
• Water in coal lowers the net energy released through combustion due to the latent heat of vaporization
• Black coal is more expensive to mine than brown coal, affecting its economic viability
• Brown coal is mined in the La Trobe Valley in Victoria
• Crude oil formation:

  <|>Formed from small marine animals and plants buried over millions of years
• Less dense than water, tends to drift up through permeable rocks and get trapped under impermeable rocks
• Crude oil is composed mostly of alkanes and can be separated through fractional distillation
• Natural gas is composed mostly of methane and other light alkanes
• Trapped in reservoirs between layers of rocks, often under impermeable rocks
• Can be found as a gaseous layer on top of crude oil deposits or bonded to coal surfaces (coal seam gas)
• Drilling releases the gas as it drifts upwards due to its lower density
• Fracking involves drilling a well and pumping chemicals, sand, and water at high pressures to release gas from coal surfaces
• Fracking can contaminate water supplies and impact the environment
• LPG is separated from crude oil through fractional distillation
• Biofuels:

  <|>Derived from plant matter such as grains like maize, wheat, and sugar cane
• Three types of biofuels are bioethanol, biogas, and biodiesel
• Energy in biofuels is derived from glucose produced through photosynthesis
• Bioethanol:

  <|>Produced through the fermentation of glucose with an enzyme catalyst
• Biogas:

  <|>Produced from the anaerobic breakdown of organic waste with anaerobic bacteria
• Leftover waste from a digester can be used as fertilizer
• Biodiesel:

  <|>Produced from the transesterification reaction of a triglyceride and methanol to form methyl esters
• Triglycerides are often sourced from vegetable or animal fats
• Energy content:

  <|>Refers to the chemical energy stored in a substance
• Energy transformations are crucial to producing useful forms of energy from fuels