07/05/2010 (Day 5)

WELCOMEhttp://plkclscmc-timothy.viviti.com/

Chapter 5The wonderful solvent - WATER

Solvent – 溶劑 A liquid that many substances can dissolve in it.

Revision: Impurities (P.55)3 types of impurities:- soluble

- insoluble- micro-organisms

How to remove impurities from water (P.58)

Sedimentation 沉積法3 different methods remove different types of impurities.

Filtration 過濾法Distillation 蒸餾法

Sedimentation 沉積法Remove large insoluble solid impurities from water.

Filtration 過濾法Remove fine insoluble solid impurities.

Removing large solid impurities by sedimentation

Alum( 明礬 )Alum makes the solid impurities to settle more quickly.

Sedimentation 沉積法

Removing large solid impurities by sedimentation

Sedimentation 沉積法

sediment

II. Using the filter paperFiltration 過濾法

residuefiltrate

Filtration 過濾法

3. The solid impurities are trapped in the filter column.

Remove fine insoluble solid impurities.

I. Using the filter columnFiltration 過濾法

4. What is the colour of the filtrate?_______________

DISCUSSIONFiltration 過濾法

Q:

Is the filtrate safe to drink? Why?

Ans. NO~ It is because the filtrate may contain soluble impurities and micro-organisms.

Distillation 蒸餾法 (P.64)Remove all soluble, insoluble impurities and micro-organisms.

Distillation

1. Boiling, 2. Condensation

Experiment 5.3(P.65)Remove impurities in water by distillation.

Experiment 5.3(P.65)Remove impurities in water by distillation.

Experiment 5.3(P.65)Remove impurities in water by distillation.

Experiment 5.3(P.65)Remove impurities in water by distillation.

Experiment 5.3(P.65)Remove impurities in water by distillation.

3.

It changes from liquid to steam.

4.

Steam changes to water.

Experiment 5.3(P.65)Remove impurities in water by distillation.

5.(a)

The distillate is colourless.5.(b)

It is water.