CHEMISTRY FORM 4 PAPER 3

Chapter 3 – Chemical Formulae and Equations

List of PEKA experiments:

1. Empirical formula of copper(II) oxide
2. Empirical formula of magnesium oxide
3. Chemical equations

Number	Activity 3.4
Pg.	23
Title	Empirical formula of copper(II) oxide
Aim	To determine the empirical formula of copper(II) oxide
Problem Statement	How does the formula of copper(II) oxide determine?
Hypothesis	The empirical formula of copper(II) oxide can be determined by finding out the mass of copper and oxygen in a sample of copper(II) oxide
Apparatus	U tube Stoppers Glass tube Combustion tube with a small hole at the end Retort stand and clamp Spatula Porcelain dish Bunsen burner Balance Preparation for hydrogen gas Thistle funnel Flat-bottomed flask
Material	Hydrogen gas, H2 Copper(II) oxide Anhydrous calcium chloride, CaCl2 Wooden splinter Preparation for the hydrogen gas Dilute hydrochloric acid Zinc pieces
Variables	Manipulated variable: Mass of copper oxide Responding variable: Mass of copper formed Controlled / Fixed variable: An excess of hydrogen gas

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Number	Activity 3.5
Pg.	25
Title	Empirical formula of magnesium oxide
Aim	To determine the empirical formula of magnesium oxide
Problem Statement	How does the formula of magnesium oxide determine?
Hypothesis	The empirical formula of magnesium oxide is MgO
Apparatus	Crucible with lid Tongs Bunsen burner Tripod stand Pipe-clay triangle
Material	10 cm magnesium ribbon Sandpaper
Variables	Manipulated variable: Magnesium ribbon Responding variable: Mass of magnesium oxide Controlled / Fixed variable: Length / Mass of magnesium ribbon and excess air

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Number	Activity 3.6
Pg.	27
Title	Chemical equations
Aim	To construct balanced chemical equations A. Heating of copper(II) carbonate B. Reaction of ammonia gas and hydrochloric acid / Formation of ammonium chloride C. Reaction of lead(II) nitrate and potassium iodide / Precipitation of lead(II) iodide
Problem Statement	How does the chemical equations determine?
Hypothesis	A. The chemical equation of copper(II) carbonate is CuCO3 –> CuO + CO2 B. The chemical equation of
Apparatus	Boiling tube Test tubes Rubber bung with delivery tube Test tube rack Test tube holder Stoppers Bunsen burner
Material	Copper(II) carbonate powder Lime water Concentrated ammonia solution Concentrated hydrochloric acid Lead(II) nitrate solution Potassium iodide solution
Variables	A. Heating of copper(II) carbonate Manipulated variable: Mass of copper(II) carbonate Responding variable: Mass of copper oxide formed / Volume of carbon dioxide liberated Controlled / Fixed variable: Pressure B. Reaction of ammonia gas and hydrochloric acid / Formation of ammonium chloride Manipulated variable: Concentration of ammonia and hydrochloric acid Responding variable: Ammonium chloride formed Controlled / Fixed variable: Temperature and pressure C. Reaction of lead(II) nitrate and potassium iodide / Precipitation of lead(II) iodide Manipulated variable: Volume of lead(II) nitrate solution and volume of potassium iodide solution Responding variable: Mass of lead(II) iodide formed Controlled / Fixed variable: Temperature and pressure