PEKA Experiment List For Chemistry Form 4 - Periodic Table

Chapter 4 – Periodic Table of Elements

List of PEKA experiments:

1. Chemical properties of lithium, sodium and potassium

Number	Experiment 4.1
Pg.	35
Title	Chemical properties of lithium, sodium and potassium
Aim	To investigate the chemical properties of lithium, sodium and potassium
Problem Statement	How does the reactivity of Group 1 elements change when they react with water and oxygen gas, O2?
Hypothesis	When going down Group 1, alkali metals become reactive in their reactions with water
Apparatus	Water troughs Small knife Forceps Gas jars Gas jar spoons Gas jar covers
Material	Small pieces of lithium, sodium and potassium Filter paper Distilled water Red litmus paper Three gas jars filled with oxygen gas, O2
Variables	Manipulated variable: Different types of alkali metals Responding variable: Reactivity of metals Controlled / Fixed variable: Water, size of metals
Operational Definition	An alkali metal that reacts more vigorously with water is more reactive metal

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2.Chemical properties of Group 17 elements

Number	Experiment 4.2
Pg.	39
Title	Chemical properties of Group 17 elements
Aim	To investigate the chemical properties of Group 17 elements (A) Reactions of halogens with water (B) Reactions of halogens with iron (C) Reactions of halogens with sodium hydroxide, NaOH solution
Problem Statement	How do halogens react with water, iron and sodium hydroxide, NaOH solution?
Hypothesis	(A) Reactions of halogens with water Halogens forms acidic solutions when they react with water 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
Apparatus	Test tubes Dropper Test tube holders Stoppers Combustion tubes Delivery tubes Bunsen burner Retort stand and clamp
Material	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
Variables	(A) Reactions of halogens with water 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
Operational Definition	(A) Reactions of halogens with water When blue litmus paper turns red, the solution formed shows acidic property 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

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3.Properties of the oxides of elements in Period 3

Number	Experiment 4.3
Pg.	45
Title	Properties of the oxides of elements in Period 3
Aim	To study the properties of the oxides of elements in Period 3
Problem Statement	How do the acid-base properties of the oxides of elements change across Period 3?
Hypothesis	Acidic properties of the oxides of elements increase whereas basic properties of the oxides of elements decrease across Period 3
Apparatus	Boiling tubes Test tubes Test tube holder Glass rod Spatula Gas jar Gas cover 100 cm3 measuring cylinder
Material	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
Variables	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
Operational Definition	Oxide that dissolves in water to form solution with pH less than 7 is acidic and pH more than 7 is alkaline Oxide that can dissolve in an acid exhibits basic properties Oxide that can dissolve in an alkali exhibits acidic properties Oxide that can dissolve in both acid and alkali exhibits amphoteric properties