Answer Happy

On a cold winter morning, you decide to make a cup of tea. You place a pan with some water from your faucet on the stove while you go take a quick shower. Unfortunately, you forget about the boiling water and, by the time you remember, the water has evaporated. A white residue remains in the pan. Which of the following procedures/observations gives the most useful information about the chemical composition of the material? a. The white material is scraped from the pan and the mass obtained. b. Addition of a small amount of vinegar (acetic acid) is added and residue dissolves as large number of bubbles form. c. The material is collected and the total volume is measured. d. A sample of cold water is allowed to evaporate and the same residue is collected. e. Distilled water does not deposit the white residue upon evaporation.