Carbon-Based Fuels

• What is a fuel?

  Substance (usually combusted) with energy in its bonds
• What is a fossil fuel?

  Natural fuel formed in Earth from organism remains
• What is coal?

  Combustible fossil fuel formed from plant matter partial decay
• What is petrol diesel?

  A fraction of crude oil (mixture of hydrocarbons), after it has undergone fractional distillation.
• What is natural gas?

  fossil fuel of gasses found in Earths crust. Mainly Methane with small amounts of other hydrocarbons.

  
  

  Found in gas reservoirs.
• What is coal seam gas?

  Natural gas sourced from coal deposits
• What is greenhouse effect?

  Warming of Earths lower atmosphere due to increased amounts of gas like CO2, water vapor and methane in the air
• Define (non)renewable resources?

  Resources that can or cannot be replenished as quickly as it is consumed
• What fossil fuels are there?

  Coal, natural gas, petrol
• What biofuels are there?

  Biogas, bioethanol, biodiesel
• Benefits of fossil fuels?

  high energy content per kilo
• Negatives of fossil fuels?

  non-renewable, natural gases are explosive, enhanced greenhouse effect, extraction causes environment issues, transportation can have spillages
• Combustion of coal?

  $C_{(s)} +$$O_{2(g)} \rightarrow CO_{2(g)}$
• Combustion of Natural Gas (methane)?

  $CH_{4(g)}+$$2O_{2(g)}\rightarrow CO_{2(g)}+$$2H_{2}O_{(l)}$
• What causes plant material to be converted from peat to black coal?

  Heat and pressure.
• How is coal energy converted to electricity?

  Burn coal, heat water to steam, steam turns turbines, turbines linked to generator which creates electricity
• What is crude oil a mixture of?

  Hydrocarbons - mainly homologous series of alkanes (differ by one CH2)
• Similarity and difference between petrol and petrol diesel?

  Similarity - both a fraction obtained from crude oil

  Difference - petrol Diesel has a longer chain of alkanes
• How is energy in Natural Gas converted to electricity?

  In a gas fired powerplant, methane + other alkanes are combusted for energy, then the hot gas expand in a combustion turbine to generate electricity.
• Compare natural gas -> electricity with coal -> electricity?

  Natural gas -> electricity is simpler than coal fired plants, since thermal energy is used to make steam
• What is Bio fuels derived from?

  Bio mass such as plants, crops and organic material
• Define carbon neutral?

  There is a net 0 release of carbon in the atmosphere due to the offset from production of the fuel.
• How is biogas produced?

  Breakdown of organic waste by anaerobic bacteria, into CO2 and CH2
• In practice, energy is required to farm, fertilise and transport biofuels, thus it may not be FULLY carbon neutral.
• How is electricity formed from biogas?

  In small-scale electricity generators, combustion of methane occurs and energy is released. But Natural gas, having more methane content, means it has more energy per gram than Biogas
• What is biodiesel and how is it formed?

  It is a mixture of esters.

  The esters are formed through Transesterification -> where triglyceride molecule is warmed with an alcohol. KOH is a catalyst in the reaction.
• Equation of Anaerobic Fermentation?

  $C_6H_{12}O_{6_(aq)} → 2C_2H_6O_{(l)} +$$2CO_{2 (g)}$