PMT flashcards chapter 16

• What is the purpose of greasing the joints in a Quickfit apparatus?

  To ensure a tight seal between pieces
• Why is continuous water flow necessary around the condenser in a distillation setup?

  To keep the water cool for effective distillation
• What is the method to separate immiscible liquids using a separating funnel?

  • Pour mixture into a separating funnel
  • Add distilled water and stopper
  • Invert to mix and equalize pressure
  • Shake until no 'whistle' sound
  • Open stopper to collect lower layer
  • Use another beaker for the organic layer
  • Shake with drying agent
• Name two drying agents used in organic chemistry.

  Magnesium sulphate and calcium chloride
• How do you use drying agents in organic chemistry?

  • Add drying agent to organic product
  • Add more if clumps form
  • Use gravity filtration to collect dry product
  • Filtrate is the final product
• What does re-distillation mean?

  Purifying a liquid using multiple distillations
• How can unsaturated hydrocarbons be tested?

  By using bromine water
• What is the observation when bromine water is added to an unsaturated hydrocarbon?

  Bromine water turns colourless
• What reagents are used to test haloalkanes and their observations?

  • Reagents: Silver nitrate, ethanol, water
  • Observations:
  • Chloro-: White precipitate
  • Bromo-: Cream precipitate
  • Iodo-: Yellow precipitate
• What are the three reagents used to test carbonyl compounds?

  • Acidified potassium dichromate
  • Fehling’s solution
  • Tollens’ reagent
• What happens when acidified potassium dichromate reacts with aldehydes?

  It turns from orange to green
• What is the observation when Fehling’s solution reacts with aldehydes?

  It forms a dark red precipitate
• What is the observation when Tollens’ reagent is reacted with aldehydes?

  A silver mirror is formed
• What reagents can be used to test carboxylic acids and their observations?

  • Universal indicator: pH of weak acid
  • Reactive metal: Hydrogen effervescence
  • Metal carbonate: Carbon dioxide effervescence