Learning focus
Develop safe and reproducible practical methods, record precise observations and measurements, process evidence and evaluate experimental quality.
Purpose
Simple distillation separates a solvent from dissolved non-volatile solute or liquids with a large boiling-point difference.
Process
Heat the mixture so the more volatile component vaporises. Vapour enters the condenser, cools and becomes liquid distillate. Non-volatile material remains in the flask.
Thermometer and condenser
The thermometer bulb measures vapour temperature near the side arm. Cooling water enters the lower end of the condenser and leaves the upper end to keep the jacket full.
Safety
Use anti-bumping measures where appropriate and never seal the apparatus. Stop before the flask boils dry. Flammable liquids require a suitable heat source rather than a naked flame.
Practical or data skill
Label a simple-distillation apparatus and explain the direction of cooling-water flow.
Examination tip
The thermometer bulb belongs at the entrance to the condenser, not immersed in the liquid.
Review questions and suggested answers
Question 1
What is collected in simple distillation?
Suggested answer
The condensed volatile component, called the distillate.
Question 2
Why does cooling water enter at the bottom?
Suggested answer
It fills the condenser jacket completely.
Question 3
Can the apparatus be sealed?
Suggested answer
No, pressure could build.
