The Mystery Powder Challenge Background Information 1. Define chemical change – 2. Define physical change – 3. Describe visible signs of a chemical change – 4. Describe some examples of a physical change -

Lab Questions/Goals 1. Which chemical changes identified compounds? 2. Which physical changes identified compounds? 3. What are the unknown powders? Process 1. Perform 5 tests on each powder 1. Cold water 2. Warm water 3. Rubbing alcohol 4. Vinegar 5. iodine 2. Compare your results to a table of properties 3. Repeat tests with questionable results if time

Table of Observations Test Solution Unknown Powder Cold water Warm water AlcoholVinegariodine Negative control Negative control A B C D E F

Table of Properties, part I Powder Cold water Warm water AlcoholVinegariodine Sodium bicarbonate sucrose Sodium chloride amylose----+

Table of Properties, part II Powder Cold water Warm water AlcoholVinegariodine Calcium carbonate Magnesium sulfate Calcium sulfate -----

What were those white powders? A. Amylose (corn starch) B. Sodium chloride (table salt) C. Sucrose (table sugar) D. Sodium bicarbonate (baking soda) E. Calcium carbonate (chalk) F. Magnesium sulfate (epsom salts) G. - control = calcium sulfate (plaster paris)

Analysis & Conclusions 1. Label each example as either a chemical change or a physical change. a. Vinegar causes baking soda to foam b. Iodine changes color when mixed with corn starch c. Epsom salt dissolves in both alcohol and water d. Sugar dissolves much better in warm water than cold water 2. Which powders did you successfully identify? 3. Which single test would be most effective to identify: a. Baking soda b. Corn starch c. Chalk d. Epsom salt