C7 - Organic Chemistry

• What type of mixture is crude oil?

  A mixture of compounds
• What general type of fuel is crude oil?

  A fossil fuel
• What is crude oil composed of?

  Remains of ancient biomass
• Is crude oil a finite or infinite resource?

  Finite resource
• What two elements exclusively make up a hydrocarbon?

  Hydrogen and carbon
• What is the general formula for alkanes?

  $C_nH_{2n+2}$
• What type of hydrocarbons are alkanes?

  Saturated hydrocarbons
• What three properties do compounds in a homologous series share?

  Same general formula, same functional groups, similar chemical properties
• What happens during the combustion of hydrocarbons?

  • Exothermic reaction between hydrocarbons and oxygen.
  • Complete combustion: carbon dioxide and water produced.
  • Incomplete combustion: carbon or carbon monoxide and water produced.
• What are the physical properties of alkanes?

  • First few are gases, then liquids, then solids.
  • Boiling points and viscosity increase as molecules get bigger.
  • Volatility and flammability decrease as molecules get bigger.
  • Poor reactivity.
• Explain how fractional distillation of crude oil takes place.

  • Crude oil is heated to 350°C and vaporised.
  • Vapour rises up the fractionating column.
  • Column is hotter at the bottom and cooler at the top.
  • Hydrocarbons condense at different heights due to different boiling points.
  • Large molecules, high boiling points - collected at the bottom.
  • Small molecules, low boiling points - collected at the top.
  • This gives fractions.
• What happens to hydrocarbons during cracking?

  They are thermally broken down
• What is the purpose of cracking?

  To break down large hydrocarbons to smaller ones
• What type of reaction is cracking?

  Thermal decomposition
• What are the two types of conditions for cracking?

  Catalytic and steam cracking
• In catalytic cracking, what state is the reactant heated to?

  Vapour
• What is mixed with the vapor in steam cracking?

  Steam
• What two types of molecules are the products of cracking?

  Alkanes and alkenes
• What are the products of cracking used for?

  Polymers and starting materials for synthesis
• What type of hydrocarbon is an alkene?

  Unsaturated hydrocarbon
• What type of bond do alkenes contain?

  C=C bond
• What is the general formula for alkenes?

  $C_nH_{2n}$
• What reagent is used to test for alkenes?

  Bromine water
• What colour change occurs when testing for alkenes?

  Orange to colourless
• Why do alkenes burn with smoky flames?

  Due to incomplete combustion
• What happens in addition reactions of alkenes?

  Atoms add across the C=C bond
• What type of bond does the double bond become in alkene addition reactions?

  Single carbon-carbon bond
• What are the types of addition reactions of alkenes?

  • With hydrogen - hydrogenation (nickel catalyst, high temperature)
  • With steam - hydration (high temperature, pressure, conc. phosphoric acid catalyst)
  • With Br2/Cl2/I2 - addition of halogens
• What functional group do alcohols contain?

  -OH functional group
• What are the characteristics of methanol, ethanol, propanol and butanol?

  • Dissolve in water to form a neutral solution.
  • React with sodium to form hydrogen.
  • Burn in oxygen.
  • React with carboxylic acids (acid catalyst) to form esters.
• What does oxidation of alcohols lead to?

  Carboxylic acids
• What are three uses of alcohols?

  Fuels, solvents, drinks
• What temperature is required for fermentation of glucose?

  30°C
• What state should the glucose be in for fermentation?

  Aqueous solution
• What condition relating to air is required for fermentation of glucose?

  Absence of air
• What substance is added to glucose for fermentation?

  Yeast
• What are the products of glucose fermentation?

  Ethanol and carbon dioxide
• What is the equation for fermentation of glucose?

  $C_6H_{12}O_6 \rightarrow 2 CH_3CH_2OH +$$2 CO_2$
• What functional group do carboxylic acids contain?

  COOH functional group
• What are the characteristics of carboxylic acids?

  • Dissolve in water to form acidic solution (contains H+ ions)
  • React with metal carbonates to form carbon dioxide
  • React with alcohols (acid catalyst) to produce esters
  • React with metals to give off hydrogen gas