University:
North Central College
Course:
CHEM 121 | General Chemistry I
Academic year:

2019
Views:

432

Pages:

2
Author:

Clint W.

Name _____________________________________ Hour______ Alchemy Lab Materials     Safety   10 mL of 3M NaOH Clean penny About 1 gram granular zinc metal Hot plate    Watch glass Bunsen Burner Tongs Goggles MUST be worn at all times NaOH is caustic—use care when heating and handling the solution Procedure 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Fill a beaker half full with water and set to the side Measure 10 mL of 3M NaOH and pour it onto the watch glass which is placed on the hot plate. Put 1 gram of granular zinc also on the watch glass. Using the tongs, place the penny on the watch glass and turn your hot plate to medium heat (make sure the solution DOES NOT boil) Flip the penny as needed using the tongs until both sides look silver Remove the penny from the evaporating dish and rinse it with water Light the Bunsen burner Holding the edges of the penny, GENTLY heat the penny with the Bunsen burner until it turns gold. Once it turns gold take it out of the heat! Heating it too long or too strong will ruin the penny. Drop the penny into the beaker of water. Remove the penny from the beaker and dry. Rinse the contents of the watch glass into the waste beaker at your lab station. DO NOT put it down the drain. Observations Post lab questions 1. Why is this lab called the alchemy lab? Did you succeed as an alchemist? 2. What metal made the penny appear silver? What made the penny appear gold in color? 3. If the penny is heated too strongly it turns back to a copper color. Suggest a reason for this. 4. Describe the following properties of metals: a. Solubility b. Conductivity c. Malleable d. Ductile 5. Describe metallic bonding. Draw a picture to help you. 6. What is a metal alloy? 7. A penny is made of what two metals? What is the name given to an alloy made from two metals found in a penny? 8. Pennies minted prior to 1982 are made of an alloy composed of approximately 98% copper and 2% zinc. a. Why might a penny be made of an alloy instead of pure copper? b. If one of these pennies were examined microscopically, it would appear uniform throughout. Would you predict the penny mixture to be heterogeneous or homogeneous