Purpose: The purpose of this lab is to learn to identify the properties of starch, sugar, baking soda, and salt. You may consider testing the following variables:
- solubility in water
- reactivity with acid
- the reaction to iodine solution (i.e. the starch test - a starch will blacken the presence of iodine)
- the response to heating
Given an unknown mixture
containing one or more
of these compounds, it should be possible to identify which compounds are present in the unknown mixture.
pipettes (plastic eye droppers)
aluminum foil squares - a disposable surface to heat
acetate sheet - a surface for mixing drops of chemicals
optional: microscale conductivity tester
vinegar (a weak acid)
iodine (a reagent to test for starch)
You will design your own procedure. Write out, step by step, what you intend to do. It is suggested that you first test the known compounds, to determine how they behave. Once you have established the individual characteristics of starch, baking soda, salt, and vinegar, you can determine which of the compounds are present in the unknown mixture
which has been assigned to you.
Create your own data
Make sure that each table
has a title. Be sure that the heading above each column is clearly labeled. The tables should be logical and well-organized.
- Summarize the individual behavior of each compound.
- State which unknown number you were assigned.
- Explain what is in your unknown mixture.
- Is your conclusion fact or opinion? Use supporting experimental evidence to support and justify your prediction.