Berry List of Chemistry Experiments (PEKA) Form 4 (Part 3)

• Water troughs
• Small knife
• Forceps
• Gas jars
• Gas jar spoons
• Gas jar covers

• Small pieces of lithium, sodium and potassium
• Filter paper
• Distilled water
• Red litmus paper
• Three gas jars filled with oxygen gas, O₂

• Manipulated variable: Different types of alkali metals
• Responding variable: Reactivity of metals
• Controlled / Fixed variable: Water, size of metals

(A) Reactions of halogens with water

(B) Reactions of halogens with iron

(C) Reactions of halogens with sodium hydroxide, NaOH solution

1. Halogens forms acidic solutions when they react with water
2. Halogens show bleaching properties when they react with water

(B) Reactions of halogens with iron

Halogens form iron(III) halides when they react with iron / When going down Group 17, halogens become less reactive in their reactions with iron

(C) ) Reactions of halogens with sodium hydroxide, NaOH solution

Halogens form sodium halide, sodium halite(I) and water when they react with sodium hydroxide / When going down Group 17, halogens become less reactive in their reactions with sodium hydroxide solution

• Test tubes
• Dropper
• Test tube holders
• Stoppers
• Combustion tubes
• Delivery tubes
• Bunsen burner
• Retort stand and clamp

• Chlorine gas, Cl₂ (produce after mixing potassium manganate(VII) salts with concentrated hydrochloric acid)
• Liquid bromine, Br₂
• Solid iodine, I₂
• Blue litmus paper
• Water
• Iron wool
• Soda lime
• 2 mol dm^-3 sodium hydroxide, NaOH solution

• Manipulated variable: Type of halogens
• Responding variable: Change in colour of the blue litmus paper / Reactivity of halogens
• Controlled / Fixed variable: Water

(B) Reactions of halogens with iron

• Manipulated variable: Types of halogens
• Responding variable: Appearance of brown solid / Reactivity of halogens
• Controlled / Fixed variable: Iron

(C) ) Reactions of halogens with sodium hydroxide, NaOH solution

• Manipulated variable: Types of halogens
• Responding variable: Formation of a colourless solution from a coloured halogen / Reactivity of halogens
• Controlled / Fixed variable: Sodium hydroxide solution

1. When blue litmus paper turns red, the solution formed shows acidic property
2. When blue litmus paper turns white, the solution formed shows bleaching property

(B) Reactions of halogens with iron

The appearance of a brown solid shows the formation of iron(III) halides

(C) ) Reactions of halogens with sodium hydroxide, NaOH solution

The formation of a colourless solution indicates that salts of sodium halide, sodium halite(I) and water are formed

• Boiling tubes
• Test tubes
• Test tube holder
• Glass rod
• Spatula
• Gas jar
• Gas cover
• 100 cm³ measuring cylinder

• Sodium oxide, Na₂O
• Magnesium oxide, MgO
• Aluminium oxide, Al₂O₃
• Silicon(IV) oxide, SiO₂
• Phosphorus pentoxide, P₂O₅
• Sulphur dioxide gas, SO₂
• Dichlorine heptoxide, Cl₂O₇
• Universal Indicator
• 2 mol dm^-3 nitric acid, HNO₃
• 2 mol dm^-3 sodium hydroxide, NaOH solution

• Manipulated variable: Oxides of elements of Period 3
• Responding variable: pH values in water and solubility in acid or alkali
• Controlled / Fixed variable: Water or nitric acid, HNO₃ or sodium hydroxide, NaOH solution

1. Oxide that dissolves in water to form solution with pH less than 7 is acidic and pH more than 7 is alkaline
2. Oxide that can dissolve in an acid exhibits basic properties
3. Oxide that can dissolve in an alkali exhibits acidic properties
4. Oxide that can dissolve in both acid and alkali exhibits amphoteric properties