Acids and Alkalis

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3.1 Alkali Metals and their Compounds

recall that the alkali metals have comparatively low melting points and boiling points

Revise physical properties of metals leading to anomalous properties of alkali metals.

describe and understand the reaction of the alkali metals with water

observe a demonstration of the reactions of sodium and potassium with water (Teacher demonstration), noting the softness, low MP and low density of the metals. Notice the solubility and alkaline nature of the product.

recall that common compounds of the alkali metals are soluble in water

Discuss examples of soluble and insoluble compounds with particular reference to alkali metal compounds.

recall that the oxides and hydroxides of the alkali metals are alkaline and are neutralised by acids to form salts

Revise preparation of soluble salts by neutralisation of alkalis using acids, emphasising the need to find reacting volumes by using a method involving the use of an appropriate indicator. Need to mix determined volumes without indicator.

3.2 pH Scale and Acidity of Aqueous Hydrogen Halides.

relate pH to acidity and alkalinity and recall the use of Universal indicator (Full range indicator) to determine pH

Discuss the pH scale as an indication of relative acidity/alkalinity; relate the scale to Universal Indicator colours.

recall that the hydrogen halides are very soluble and understand how they can be dissolved safely

Demonstrate that HCl is very soluble by the 'fountain experiment'. Demonstrate the use of an inverted filter funnel to dissolve HCl in water; test the resulting solution with Universal Indicator.

recall that hydrogen halides dissolve in water to produce acidic solutions

Demonstrate small scale production of HCl/HBr/HI, testing the gases with damp pH paper.

3.3 Useful Halides

Recall the use of fluorides in the water supply and in toothpaste and of silver halides in photography

Discuss arguments for and against the fluoridation of water.

3.1 Alkali Metals and their Compounds
recall that the alkali metals have comparatively low melting points and boiling points	Revise physical properties of metals leading to anomalous properties of alkali metals.
describe and understand the reaction of the alkali metals with water	observe a demonstration of the reactions of sodium and potassium with water (Teacher demonstration), noting the softness, low MP and low density of the metals. Notice the solubility and alkaline nature of the product.
recall that common compounds of the alkali metals are soluble in water	Discuss examples of soluble and insoluble compounds with particular reference to alkali metal compounds.
recall that the oxides and hydroxides of the alkali metals are alkaline and are neutralised by acids to form salts	Revise preparation of soluble salts by neutralisation of alkalis using acids, emphasising the need to find reacting volumes by using a method involving the use of an appropriate indicator. Need to mix determined volumes without indicator.
3.2 pH Scale and Acidity of Aqueous Hydrogen Halides.
relate pH to acidity and alkalinity and recall the use of Universal indicator (Full range indicator) to determine pH	Discuss the pH scale as an indication of relative acidity/alkalinity; relate the scale to Universal Indicator colours.
recall that the hydrogen halides are very soluble and understand how they can be dissolved safely	Demonstrate that HCl is very soluble by the 'fountain experiment'. Demonstrate the use of an inverted filter funnel to dissolve HCl in water; test the resulting solution with Universal Indicator.
recall that hydrogen halides dissolve in water to produce acidic solutions	Demonstrate small scale production of HCl/HBr/HI, testing the gases with damp pH paper.
3.3 Useful Halides
Recall the use of fluorides in the water supply and in toothpaste and of silver halides in photography	Discuss arguments for and against the fluoridation of water.