Chemical Reaction Demonstrations Answer Key
The One With The Egg & Vinegar
WE:
acetic acid + calcium carbonate → calcium acetate + water + carbon dioxide
BCE: 2HC2H3O2(aq) + CaCO3(s) → Ca(C2H3O2)2(aq) + H2O(l) + CO2(g)
The One With The Two Iron Balls
WE:
aluminum + iron(III) oxide → iron + aluminum oxide
BCE: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s)
The One With The Pop Can
WE:
aluminum + copper(II) chloride → copper + aluminum chloride
BCE: 2Al(s) + 3CuCl2(aq) → 3Cu(s) + 2AlCl3(aq)
The One With The Precipitate
WE:
copper(II) chloride + sodium carbonate → sodium chloride + copper(II) carbonate
BCE: CuCl2(aq) + Na2CO3(aq) → 2NaCl(aq) + CuCO3(s)
The One With The Two Balloons
Reaction 1: Production of Ethyne
WE:
calcium carbide + water → ethyne + calcium hydroxide
BCE: CaC2(s) + 2H2O(l) → C2H2(g) + Ca(OH)2(s)
-the calcium hydroxide has a low solubility (the white solid formed) although some will be in a
dissolved state (dissolved Ca2+ and OH- ions)
Reaction 2: Combustion of Ethyne
The combustion that produced no or very little soot is more of a complete combustion:
WE:
ethyne + oxygen → carbon dioxide + water
BCE: 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)
The combustion that produced a lot of soot is incomplete combustion:
Possible WE: ethyne + oxygen → carbon soot + carbon monoxide + carbon dioxide + water
Possible BCE: 4C2H2(g) + 5O2(g) → 4C(s) + 2CO(g) + 2CO2(g) + 4H2O(g)
The One With Sulfur
WE:
sulfur + oxygen → sulfur dioxide
sulfur dioxide + oxygen → sulfur trioxide
sufur trioxide + water → sulfuric acid
BCE: S(s) + O2(g) → SO2(g)
-sulfur exists as S8 molecules but for simplicity S is commonly used
2SO2(g) + O2(g) → 2SO3(g)
SO3(g) + H2O(l) → H2SO4(aq)
The One With “Swag”
- the blue flame indicated that the ethanol underwent more of a complete combustion
WE:
ethanol + oxygen → carbon dioxide + water
BCE: C2H6O(l) + 3O2(g) → 2CO2(g) + 3H2O(g)
The One With Poor Ol’ Mr. Gummie Bear
Reaction 1: Decomposition of Potassium Chlorate
WE:
potassium chlorate → potassium chloride + oxygen
BCE: 2KClO3(s) → 2KCl(s) + 3O2(g)
Reaction 2: Combustion of Glucose
For simplicity, we will assume that only glucose underwent combustion and that the combustion
was complete. Due to the presence of other combustible, carbon-containing chemicals present in
the gummie bear, it was evident in class that incomplete combustion occurred.
WE:
glucose + oxygen → carbon dioxide + water
BCE: C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(g)
The One With The Pringles Can
Reaction 1: Production of Hydrogen and Zinc Chloride
WE:
zinc + hydrochloric acid → hydrogen + zinc chloride
BCE: Zn(s) + 2HCl(aq) → H2(g) + ZnCl2(aq)
Reaction 2: Combustion of Hydrogen
WE:
hydrogen + oxygen → water
BCE: 2H2(g) + O2(g) → 2H2O(g)
The One With Sodium
Reaction 1: Production of Hydrogen and Sodium Hydroxide
WE:
sodium + water → hydrogen + sodium hydroxide
BCE: 2Na(s) + 2H2O(l) → H2(g) + 2NaOH(aq)
Reaction 2: Combustion of Hydrogen
WE:
hydrogen + oxygen → water
BCE: 2H2(g) + O2(g) → 2H2O(g)