Name

Period

Date

Zinc Penny Lab

OBJECTIVE

• Work lab calculations to a specific
• decimal place
• significant digit.

INFO

• Zn + 2HCl ---> ZnCl₂ + H₂
• penny is 97.5% zinc
• Zn = 65.39 g/mol
• H₂ = 2.02 g/mol

MATERIALS

• penny newer than 1982
• triangular file, 50-mL beaker
• 25 mL 6M HCl

DATA

1. mass of penny before = g
2. mass of penny after = g

PROCEDURE

1. Score 6 equally spaced grooves through penny's rim.
2. Measure penny's 'before' mass.
3. Label the 50-mL beaker.
4. Place penny and HCl acid in the 50-mL beaker, and cover with a glass plate.

*** DAY TWO ***

5. Use a screen to carefully remove the penny from the acid.
6. Place penny on paper towel to wick out liquid from inside.
7. Dip penny into acetone, then place on paper towel for a couple minutes.
8. Measure penny's 'after' mass.
9. Get answers for calculations from computer.
10. Scrub beaker and glass plate clean with soapy water & scrubbie

CALCULATIONS(Show all work.)

1. calculated mass of zinc in penny (WYSHG) = g
2. actual mass of reacted zinc (WYG) = g
3. percent discrepancy for reacted Zn = g
4. theoretical mass of produced H₂ = g
• use the actual mass of reacted Zn, #2
5. theoretical mass of produced H₂ = g
• #4 written to three significant digits