Organic chemistry

• Boiling point increases with alkane chain length
• Any more than 4 carbons are liquid at room temp
• Shorter alkanes evaporate easier due to low boiling point
• Shorter alkanes are more flammable
• Alkanes are used for fuel
• Complete combustion is an exothermic reaction
• Properties of alkanes depend on chain length
• What analytical technique is used to separate substances in a mixture?

  Chromatography
• What is the specific type of chromatography discussed in the video?

  Paper chromatography
• What is the purpose of paper chromatography?

  To separate different dyes in ink
• What is the first step in paper chromatography?

  Draw a baseline with a pencil
• Why is the solvent in paper chromatography kept shallow?

  To avoid submerging the pencil line
• What happens to the different dyes during chromatography?

  They travel at different rates up the paper
• What is the pattern of spots left after chromatography called?

  Chromatogram
• What are the two phases in chromatography?

  Mobile phase and stationary phase
• What is the mobile phase in paper chromatography?

  The solvent used in the process
• What is the stationary phase in paper chromatography?

  The filter paper used for separation
• How do different chemicals behave in the mobile and stationary phases?

  They dissolve and bind repeatedly
• What determines how fast a chemical moves up the paper?

  Solubility in the solvent
• What is the formula for calculating the rf value?

  Distance travelled by substance / distance travelled by solvent
• If a pink substance travels 6 cm and the solvent travels 10 cm, what is the rf value?

  $0.6$
• What happens when chromatography is performed with a pure substance?

  It produces a single spot on the chromatogram
• How can changing the solvent or paper affect chromatography results?

  It can change the chromatogram appearance
• Why must chemists consider the solvent and paper type when looking up rf values?

  Because they affect the chromatogram results
• What should you do to prevent solvent evaporation during chromatography?

  Place a lid on the beaker