Explain the purposes of these stages in the isolation process:
- the use of propane
- using filter paper and funnel
- re-crystallisation

- Use of propane? I haven't a clue, unless it's as a fuel to heat something up. When you learn the answer, let me know.

- filter paper and funnel - to separate out solids from a solution.

- re-crystallization - to purify impure materials.