1. Penny lab

2. Precautions Follow all lab safety rules Wear goggles and aprons
Make sure your penny is clean and shiny
Zinc chloride is corrosive if it falls on your skin – inform the instructor and wash under cold water
Do not allow the zinc chloride solution to boil

3. Precautions
Granulated zinc is combustible do not add water to it follow teacher instruction to dispose off
Use forceps to put and remove pennies from the beaker . Do not drop them in beaker
Use tongs to hold the hot beaker
rinse the zinc treated penny in in water and pat dry with a paper towel
Heat gently on the hot plate over heating will result in penny changing back to a copper color
follow teacher instructions for disposal of zinc chloride and zinc
wash hands

4. Post 1982
Pre 1982

5. Obtain 3 pre 1982 pennies
Use vinegar and salt mixture to clean the pennies followed by cleaning them with steel wool

6. Preparation of "Gold" Pennies
Part 2
Procedure
1. Place ~1 g of granular zinc in an beaker dish on a hot plate.
2. Add ~ 10 ml of 1 M zinc chloride and cover with a watch glass.
3. Bring the solution to a gentle bubbling not boiling .
4. Add a penny, cover and simmer until the penny becomes silvery. Stir it occasionally.
5. Use tongs to remove the penny from the evaporating dish and rinse it with water.
Part 3
Rinse in water and pat dry
6. GENTLY heat the penny in a hot plate until it turns to gold. forth while heating. You can ruin your penny by overheating it.
7. Drop the penny in a beaker of water. Remove the penny from the beaker and dry.

7. Post pennies
To conserve copper and reduce costs, the penny has been made of 97.5%
zinc and 2.5% copper,

8. Brass
Zinc
Copper 8

9. http://bcs. whfreeman. com/chemcom5e/content/cat_010/CC5e_Main_www

10. An alloy
An alloy is a material that contains more than one element and has the characteristic properties of metals.
primary ways of modifying the properties of pure metallic elements.
As an example, pure gold is extremely soft to use to make jewelry
-14 karat gold – an alloy meaning that it is 58 percent gold

11. Alloys Wood’s metal 50% Bi, 25% Pb, 12.5% Sn, 12.5% Cd
Uses - Fuse plugs, automatic sprinklers
Yellow brass 67% Cu, 33% Zn uses - Hardware items
Steel > 97 % Fe, < 3% C Steel Uses -chain, girders, tools
Stainless steel 80.6% Fe, 0.4% C, 18% Cr, 1% Ni ---Tableware
Plumber’s solder 67% Pb, 33% Sn -----Soldering joints
Sterling silver 92.5% Ag, 7.5% Cu -----Tableware
Dental amalgam 70% Ag, 18% Sn, 10% Cu, 2% Hg Dental fillings