1. % Composition of a Penny Lab (1 of 4) DMA: Observe the reactions of hydrochloric acid, HCl, with both copper & zinc. What is the difference? A penny is composed of copper around zinc. Estimate the % of copper & zinc in a penny. Re-estimate at the end of class.

2. % Composition of a Penny Lab (2 of 4) Materials: digital scale, metal file, penny, 25ml of 6M HCl/penny, 100 ml beaker Given the materials above, write procedures that would allow you to determine the % of copper and zinc in a penny.

3. Day 1 – Procedures (3 of 4) 1.Make data table as directed. 2.Observe penny’s year & condition. 3.Weigh penny on digital scale. 4.File copper off side of penny at 4 spots to expose zinc. 5.Label beaker w/ initials & period. 6.Pour 25 ml of 6M HCl into beaker. (50 for 2) 7.Place both pennies in the acid & observe. 8.Store overnight in cabinet.

4. Day 2 Procedures 1.Observe the condition of the pennies repeatedly. 2.Decant the liquid into the hazardous waste. 3.Rinse out penny with water & pour down the sink 4.Dab dry the penny with a paper towel & on the hot plate for several minutes. 5.Remass the pennies. 6.Tape the hollow penny into your lab notebook as proof of completion. 7.Show your lab notes & hollow penny to the instructor for a grade.

5. % Composition of Penny Lab Report (1 of 2) Include: Title Prelab Observations (DMA) Purpose Hypothesis Materials Step by Step Procedures Data Table with Item/Measurements/Observations

6. % Composition of Penny Lab Report (1 of 2) Calculations – Item / Formula / Work / Answer for each. Sources of Error – Real ones /not maybes or could haves. Conclusions – Restate hypothesis, evaluate hypothesis, use #s to justify your evaluation, relate lab to real life beyond pennies.