fuels and crude oil

• fossil fuels are non renewable sources of energy
• fossil fuels are formed from decayed plants & animals from millions of years ago. they are mainly organic substances that contain hydrocarbons
• fuels are substances which produce a large amount of thermal energy during combustion
• combustion is a process where fossil fuels are burnt in the presence of oxygen to form water and carbon dioxide
• the chemical equation for burning methane (natural gas) is CH4 + 2O2 -> CO2 + 2H2O
• fossil fuels + oxygen -> carbon dioxide + water
• what are the main components of fossil fuel

  natural gas and crude oil
• natural gas


  colorless and contains mainly methane
• crude oil is a dark brown liquid with a mixture of hydrocarbons, mainly alkanes
• what is natural gas used for?

  to power our stoves during cooking
• natural gas is odorless and colorless
• crude oil/petroleum is a liquid with a range of colour and smell
• crude oil is a mixture of hydrocarbons
• crude oil reservoirs can be found beneath oceans and land floors
• crude oil has to be separated into different groups before each group can be used
• why is there a need to conserve crude oil and natural gas?

  there are limited quantities of natural gas and crude oil. they are non renewable and it takes a very long time for them to form
• crude oil can be separated by fractional distillation
• hydrocarbons in petroleum have different boiling points
• each component of petroleum is a mixture of hydrocarbons which boils over a range of temperature
• lowest boiling point with less carbon atoms is collected at the top of the fractionating column
• highest boiling point with bigger molecules is collected at the bottom of the fractionating column
• how is crude oil separated into fractions?

  1. in the furnace at the bottom of the fractionating column, crude oil is heating until it becomes a mixture

  2. the vapour is pumped into the fractionating column to get separated

  3. smaller hydrocarbons with less carbon atoms and low boiling are collected at the top of the fractionating column as gases

  4. bigger hydrocarbons with more carbon atoms are and high boiling point are collected at the lower section of the fractionating column
• fuel is used for cooking
• fuel has the lowest boiling point because of less carbon atoms and is distilled over first
• petrol is used as fuels for cars
• naptha is feedstock for making of plastics and cosmetics
• kerosene is fuel for aircraft engines
• diesel oil is fuel for lorries or buses
• lubricating oil is for making of waxes and polishes
• bitumen is used for making of road surfaces
• bitumen has the highest range of boiling point because of more carbon atoms and is distilled over last
• fossil fuels are not environmentally friendly


  carbon dioxide is one of the main products of burning crude oil + natural gas. it is a greenhouse gas and contributes to global warming. pollutants like sulfur dioxide is also formed and hence we need to reduce the use of fossil fuels and find other alternatives
• biofuels are renewable sources of energy
• another name for biofuel is ethanol
• ethanol can be obtained from the fermentation of sugar from sugarcane plants
• biofuels come from plants and animals. they can be replaced relatively fast after use
• bioethanol is considered renewable as sugarcane plants can be renewed and replenished after use
• advantages of biofuels compared to fossil fuels

  more environmentally sustainable and renewable
• biofuels are more environmentally sustainable as, sugarcane takes in carbon dioxide during photosynthesis which offsets the carbon dioxide produced by bioethanol
• sugarcane -> bioethanol -> burned to get carbon dioxide