paper 2 chemistry

• what is a pure substance?

  A substance that is made up of only one type of particle or molecule.
• why is paper in the pure substance practical the stationary phase?

  because it doesnt move
• why is solvent the mobile phase?


  because it moves
• how does paper chromatography separate mixtures?

  as solvent soaks the paper, it carries the mixtures with it
• what is the formula for alkanes


  CnH2 n+2
• what happens when the size of a hydrocarbon increase

  • molecules become more viscous
  • becomes less flammable
  • boiling point increases
• what does flammability tell us about hydrocarbons

  how easily they combust
• viscosity

  tells us thickness of a fluid
• what is the test for alkenes

  orange bromine water turning to colourless
• what is an alkane

  hydrocarbons with single bonds only
• how are hydrocarbons separated into fractions

  fractional distillation
• hydrocarbon

  a compound made up of hydrogen and carbon only
• what can fractions of hydrocarbons be processed into

  fuel
• how do you detect a mixture

  compounds may separate into different spot depending on the solvent
• crude oil definition

  • a finite resource found in rocks
  • remains of ancient biomass such as plankton buried in mud
  • a mixture of a very large number of compounds
• how and why are hydrocarbons cracked

  • long hydrocarbons are unuseful
  • cracked using heat and a catalyst
• how to detect a pure compound in a solvent

  a single spot will be produced in all solvents
• how to distinguish pure substances from mixtures

  boiling and melting point
• what is a formulation?give examples

  a complex mixture that has been designed for a useful product

  • examples - fuels, medicine, cleaning products, food