Question

* For each step write a balanced equation. Make sure to indicate the phases of material.

Step 1: An aluminum soda can will be used as the source of aluminum in this synthesis. The solid aluminum is dissolved in an aqueous solution of 4 M KOH (the 4M refers to the concentration, 4 moles of KOH per L of solution) in the presence of water. During this reaction, the dihydrogen gas escapes into the atmosphere and an aqueous product of potassium aluminum hydroxide is formed.

Step 2: After solid impurities are removed by filtration, 9 M aqueous sulfuric acid (H2SO4) is then added to the potassium aluminum hydroxide aqueous solution. Initially, aluminum hydroxide precipitates as a solid out of solution, also forming water, and potassium sulfate

Step 3: Additional sulfuric acid is added to neutralize the basic aluminum hydroxide, forming aqueous aluminum sulfate and water.

Step 4: At this point, the solution contains aqueous potassium ions, aluminum ions, and sulfate ions and water. An ice bath is used to cool the solution and to help combine the ions and water to form a crystalline solid hydrate, called potassium aluminum sulfate dodecahydrate. We can then perform a filtration to separate the solid crystalline hydrate from the solution and isolate the solid.

Answer 1