Grade Level: 9th to 10th; Type: Chemistry
In this experiment you will be making a compound of different elements by taking iodine and zinc and combining them to make zinc iodide.
- If you add the mass of zinc and iodine together, how would it relate to the zinc iodide compound?
- Do your results prove or disprove the Law of Conservation of Mass?
- How are the original elements different from the compound produced in this experiment? i.e. color, shape, etc.
- Granular zinc (10 – 50) mesh
- Iodine crystals
- Hot hands gripping pad
- Vinegar (0.9M acetic acid)
- Weighing dishes
- Hot plate
- Stir rod
- Copper (platinum) electrodes
- 50mL Erlenmeyer flask
- 125mL Erlenmeyer flask
- 10mL Graduated cylinder
- Electronic balance
- Scoops (Spatulas)
- Petri Dish
- 9 V battery
- Alligator leads (2)
- Add 2g of iodine, followed by 2g of granular zinc to the 50mL flask.
- Add 5mL of vinegar and swirl. Wait for the color to stop changing and result to a clear liquid.
- You should now only have zinc and liquid in your Erlenmeyer flask.
- Place the liquids into a 125mL flask while leaving the solid zinc in the 50mL flask.
- Rinse the remaining zinc with 1mL of vinegar three times. Add the rinses to the 125mL flask.
- What you have now in the 125mL flask, is a zinc iodide solution. Heat this solution on the hot plate with a low setting. The solid zinc iodide will come out of the solution as the water is boiled away. You are done when the zinc iodide turns an off-white or light yellow color. Do NOT let it turn dark yellow or orange. This is indicating that it has started to decompose because it is being heated too strongly.
- You should now have solid zinc iodide. Congratulations, you have made a compound!
Terms/Concepts: compounds, elements, isolating, mixtures, solutions, decomposition
Elements and compounds: http://www.qldscienceteachers.com/junior-science/chemistry/elements-and-compounds.
Chemical decomposition: http://www.chemteam.info/Equations/Decomposition.html.