2020 Paper 2

• Complete the diagram in Figure 2 to show how the hydrogen gas could be collected and measured in the experiments in Questions 01.1 and 01.2. [1 mark]

  • Tubing should not be closed
  • Syringe should have a PLUNGER! shown
  • Allow lack of graduations

  
• Define the term overall order of reaction.

  • The sum of powers/indices to which the concentrations are raised in the rate equation
• Separate samples of each isomer are warmed with ethanoic acid and a few drops of box concentrated sulfuric acid.

  Suggest a simple way to detect if the ethanoic acid reacts with each isomer.

  • SWEET SMELLING LIQUID
• Distinguishing between 2 same functional groups, using fingerprint region

  • M3 R & S (unique) fingerprint region or below 1500 cm−1
  • M4 Compare to a database / known spectra (and look for an exact match)
• Identify a hazard of using concentrated phosphoric acid [1 mark]

  • Corrosive
  • Accept:
  • Skin burn
  • Permanent eye damage
  • NOT irritant / toxic
• Suggest a suitable piece of apparatus to measure out the ethanoic anhydride in step 5.

  • 10 cm3 measuring cylinder (if volume given – allow between 10 to 50 cm3 )
  • Or a 10 cm3 pipette Or
  • burette / graduated pipette
  • Or 10 cm3 syringe
• The pure aspirin is filtered under reduced pressure. A small amount of cold ethanol is then poured through the Buchner funnel. Explain the purpose of adding a small amount of cold ethanol. [1 mark]

  • To remove any soluble impurities
  • Allow To avoid aspirin dissolving (small amount cold solvent used)
  • Allow To remove/(wash away) any ethanolic solution on the product
• MISTAKE =

  • For propane, it is THREE carbons, not four.
  • My elephant PREFERS (3 carbons) Bananas (4 carbon)
• Using TMS (Tetramethylsilane) as a reference

  • 3b Signal in an area away from other typical H signals / peak upfield from others