added

• How is crude oil formed?

  Over millions of years from the fossilised remains of plankton
• Where is crude oil found?

  In the porous rocks in the Earth's crust
• What is crude oil made up of?

  Hydrocarbons
• What gives hydrocarbon molecules varying properties?


  They vary in size
• What happens to the properties of hydrocarbons as the molecules get larger?

  It gets more viscous, its boiling point gets higher, the less volatile it is, the less easily it ignites
• How are the components of crude oil separated?

  Fractional distillation
• Why does fractional distillation work?


  Different sized molecules of hydrocarbons have different boiling points
• What piece of equipment does fractional distillation take place in?

  Fractionating column
• What are the stages of fractional distillation?

  1) the crude oil is heated until it evaporates 2) the molecules move up the fractionating column which is hotter at the bottom 3) larger molecules condense at the hotter bottom of the column and are collected 4) the shorter molecules condense at the cooler top of the column and are collected
• What is an alkane?

  A hydrocarbon in which each carbon molecule makes 4 single bonds with other molecules
• Are alkanes saturated or unsaturated?

  Saturated
• What is the general formula for an alkane?

  CnH2n+2
• What is the name of an hydrocarbon with 1 carbon molecule?

  Meth(ane/ene)
• What is the name of an hydrocarbon with 2 carbon molecules?

  Eth(ane/ene)
• What is the name of an hydrocarbon with 3 carbon molecules?

  Prop(ane/ene)
• What is the name of an hydrocarbon with 4 carbon molecules?

  But(ane/ene)
• What is the name of an hydrocarbon with 5 carbon molecules?


  Prop(ane/ene)
• What happens during the combustion of hydrocarbons?

  Carbon and hydrogen are oxidised, energy is released, waste products are released into the atmosphere
• What happens in incomplete combustion?

  Carbon monoxide is produced which is poisonous. Soot is given off
• What is the effect of particulates?

  They cause global dimming by reducing the amount of sun that can reach the earth's surface, they cause damage to people's lungs
• How are nitrogen oxides produced from combustion?


  When high temperatures from combustion are reaches, nitrogen in the air reacts with oxygen
• What problems do nitrogen oxides cause?

  Cause respiratory problems, react with rainwater to form acid rain
• What has been done to try and reduce the amount of sulfur released into the atmosphere?


  It can be removed from fuels before combustion in motor vehicles or removed from waste gases in power stations
• What is the balanced symbol equation for complete combustion?

  C + O2 = CO2
• What is the balanced symbol equation for incomplete combustion?

  2C + O2 = 2CO
• What is the balanced symbol equation for the combustion of hydrogen?

  2H2 + O2 = 2H2O
• What is the balanced symbol equation for the combustion of sulfur?

  S + O2 = SO2
• What is cracking?

  Long chain hydrocarbons being split into shorter chain hydrocarbons
• What does the process of cracking include?

  1) the hydrocarbons are heated until they vaporise 2) the vapour is passed over a hot catalyst 3) thermal decomposition then takes place
• What are the products of cracking?

  Both alkanes and alkenes
• Why are hydrocarbons split into shorter molecules?


  There is a higher demand for short hydrocarbons as they easy to ignite and have low boiling points so are used in fuels
• What is the main difference between alkenes and alkanes?

  Alkenes have a double carbon-carbon bond
• What are hydrocarbons that have double bonds described as?

  Unsaturated
• What is the general formula for an alkene?

  C(n)H(2n)
• Why are alkenes more reactive than alkanes?

  Because of the C=C bond
• Why do alkenes burn with a smokier flame than alkanes?

  They go through incomplete combustion
• What can be added to alkenes to produce alkanes?

  Hydrogen
• What catalyst is used in the addition reaction used to produce alkanes from alkenes?

  Nickel
• How can ethanol be produced?

  By reacting ethene with steam in the presence of a catalyst- phosphoric acid
• What test can be used to differentiate between alkanes and alkenes?

  bromine water