PEKA Experiment List For Chemistry Form 4 - Structure of Atom

Chapter 2 – The Structure of the Atom

List of PEKA experiments:

1. Diffusion of particles in a gas, liquid and solid

Number	Activity 2.1
Pg.	7
Title	Diffusion of particles in a gas, liquid and solid
Aim	To investigate the diffusion of particles in a gas, liquid and solid
Problem Statement	How diffusion does occur through solid, a liquid and gas?
Hypothesis	Particles can diffuse through the spaces between the particles of a solid, a liquid and the gas.
Apparatus	A. Diffusion in a gas Gas jars Gas jar covers B. Diffusion in a liquid Droppers / Teat pipette Thistle funnel Spatula C. Diffusion in a solid Stoppers Test tubes Test tube rack Retort stand and clamp
Material	A. Diffusion in a gas Liquid bromine, Br2 B. Diffusion in a liquid 1 mol dm-3 potassium manganate (VII), KMnO4solution Water C. Diffusion in a solid Potassium manganate(VII), KMnO4 crystal / Copper(II) sulphate, CuSO4 crystal Hot liquid gel
Variables	Manipulated variable: Type of medium Responding variable: Motion of the particles Controlled / Fixed variable: Temperature and pressure

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2. Rate of diffusion depends on the temperature

Number	Activity 2.2
Pg.	8
Title	Rate of diffusion depends on the temperature
Aim	To show that the rate of diffusion depends on the temperature
Problem Statement	How does rate of diffusion depends on the temperature?
Hypothesis	Higher temperature can increase the rate of diffusion
Apparatus	Beakers Droppers
Material	Food colouring Water Ice water Hot water
Variables	Manipulated variable: Temperature of water Responding variable: Rate of diffusion Controlled / Fixed variable: Concentration and volume of food colouring and pressure
Operational Definition	Higher temperature in water increases the particles to move faster and increases the rate of diffusion. / Higher temperature in water increases the kinetics energy than lower temperature in water.

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3. Rate of diffusion depends on the mass of the gas particles

Number	Activity 2.3
Pg.	9
Title	Rate of diffusion depends on the mass of the gas particles
Aim	To show that the rate of diffusion depends on the mass of the gas particles
Problem Statement	How does rate of diffusion depends on the mass of the gas particles?
Hypothesis	Low molecular masses diffuse faster than those with high molecular masses
Apparatus	Glass tube Stoppers Retort stand and clamp Beakers Droppers
Material	Glass wool Concentrated ammonia, NH3 solution Concentrated hydrochloric acid, HCl
Variables	Manipulated variable: Mass of the gas particles Responding variable: Rate of diffusion Controlled / Fixed variable: Temperature and pressure
Operational Definition	Gas with low molecular masses diffuse faster than those with high molecular masses.

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4. Melting and freezing points of naphthalene, C₁₀H₈

Number	Activity 2.4
Pg.	9
Title	Melting and freezing points of naphthalene, C10H8
Aim	To determine the melting and freezing points of naphthalene, C10H8
Problem Statement	How does rate of diffusion depends on the mass of the gas particles?
Hypothesis	The temperature of naphthalene, C10H8 increase during heating except at its melting and solidification points
Apparatus	Boiling tube 250 cm3 beaker Thermometer (0 – 100˚C) Tripod stand Retort stand and clamp Bunsen burner Stopwatch Conical flask Wire gauze
Material	Naphthalene, C10H8 Water
Variables	Manipulated variable: Heat supplied Responding variable: Temperature Controlled / Fixed variable: Naphthalene, C10H8