Evaporation and crystallization of common salt
Dissolve salt in water, then heat the solution until the water has gone and crystals remain.
Objectives
- Prepare a solution.
- Separate a dissolved solid from its solvent by evaporation.
- Use a Bunsen burner safely.
Theory
A soluble solid cannot be separated from its solution by filtration because its particles pass through the filter paper. Heating evaporates the solvent and leaves the solute behind as crystals.
Procedure
- Put on your safety goggles and lab coat.
- Place an evaporating dish and add about 30 mL of distilled water.
- Dissolve about 5 g of sodium chloride in it.
- Place a Bunsen burner and move the dish onto its tripod.
- Light the burner and heat until the solution boils.
- Keep heating until all the water has evaporated and crystals remain.
- Turn off the burner.
Precautions
- Turn off the burner as soon as the dish is dry.
- Never touch the hot dish.
- Subject
- Chemistry
- Grade
- 8–9
- Chapter
- Matter (Nepal National Curriculum (CDC), grade 8)
- Difficulty
- Easy
- Duration
- 20 min
- Safety level
- Medium
- Version
- 1.0
Apparatus
- Evaporating dish
- Bunsen burner with tripod
Chemicals
- Distilled water H₂O
- Sodium chloride NaCl
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