Qualitative inorganic analysis: a way of identifying ions in aqueous solution (water). The solution is then treated with reagents to test for reactions characteristic of certain ions, which may cause color change, solid forming and other obviously visible changes.

Before you begin....

  • Define the following terms...
    • Soluble
    • Insoluble
    • Precipitate
  • Determine the oxidation numbers for Fe, Zn, Cd, Na, Cl, and S.
    • Think in terms of chemical bonding.
    • Hint: Use the MSDS links (look to the right).

The goal of this lab is to identify which positive ion is present in an unknown solution using 'qualitative inorganic analysis'.

  • Step 1: Standard Solution Reactions
    • You have four 1.5ml vials
    • There are four stations, each with a different standard solution.
    • SEPERATLY, fill each vial HALF WAY with each of the 4 standard solutions.
    • Pipette a few drops of the sodium sulfide solution into the Fe, Zn, and Cd vials.
    • Observe what happens.
    • Record what you see on your wiki page.
  • Step 2: Use what you learned from Step 1 to identify the unknown solution provided.

Now that the lab is complete, lets connect it to what we have been learning about the chemistry that takes place near hydrothermal vents.

  • Relate the observations made during the lab to the pictures of hydrothermal vents you have collected.
    • What are the main ions present in the 'smoke' for each of your pictures.
  • Describe the chemical process that takes place within a hydrothermal vent using the terms soluble, insoluble, and precipitate that you defined earlier.
 

MSDS

Standard Solutions

Iron Chloride

Zinc Chloride

Cadmium Chloride

Sodium Sulfide

Products

Iron Sulfide

Zinc Sulfide

Cadmium Sulfide