FOR FULL CREDIT, SHOW DETAILED CALCULATION SETUPS. REMEMBER TO FOLLOW THE SIGNIFICANT FIGURES CONVENTION, AND TO SHOW MEASUREMENT UNITS FOR EACH QUANTITY.
1. What causes the Al clippings to rise and fall as they are being dissolved in the KOH solution?
2. The synthesis of alum proceeds in several reaction steps. The mole ratios of reactants and products can be found by combining the written equations for these separate reactions into an overall equation. Balance the overall equation for the synthesis of alum, KAl(SO4)2 • 12 H2O, from aluminum, potassium hydroxide, sulfuric acid and water. HINT: Add together the four equations given in the introduction, canceling out any molecules or formula units that appear on both sides.
Al + KOH + H2SO4 + H2O → KAl(SO4)2 •12 H2O + H2
3. Look at the equations given in the experiment; identify the oxidation-reduction reactions in which the oxidation number of an element changes.
4. Explain why aluminum reacts slowly with dilute acids.
5. Balance the following equation:
KOH + Al2O3 + H2O → KAl(OH)4