Chemistry Key Processes

• Define chain isomerism


  Same molecular formula, but different arrangement of C atoms.
• Define positional isomerism


  Same molecular formula, but different position of functional groups.
• Define nucleophile


  A species attracted to electron-deficient C atom & donates a pair of electrons to form a new bond.
• By what mechanism do alkanes react?


  Free-radical substitution.
• By what mechanism do alkenes react?

  Electrophilic addition.
• By what mechanism do haloalkanes react?

  Nucleophilic substitution & elimination.
• By what mechanism do alcohols react?

  Substitution or elimination.
• What is the test for aldehydes?

  Tollens' Reagent to form a 'silver mirror' or Fehling's Solution to observe a colour change from blue to red.
• How do you ensure accurate titration?

  1. When reading the burette, have eyes level with the solution and read the bottom of meniscus curve
  2. Have a white tile underneath the conical flask to see clear colour change
  3. Have concordant titres within 0.1cm^3 of each other