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% Composition of a Penny Lab (2 of 4). Materials: digital scale, metal file, penny, 25ml of 6M HCl/penny, 100 ml beakerGiven the materials above, write procedures that would allow you to determine the % of copper and zinc in a penny.. Day 1
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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) Make data table as directed.
Observe penny’s year & condition.
Weigh penny on digital scale.
File copper off side of penny at 4 spots to expose zinc.
Label beaker w/ initials & period.
Pour 25 ml of 6M HCl into beaker. (50 for 2)
Place both pennies in the acid & observe.
Store overnight in cabinet.
4. Day 2 Procedures Observe the condition of the pennies repeatedly.
Decant the liquid into the hazardous waste.
Rinse out penny with water & pour down the sink
Dab dry the penny with a paper towel & on the hot plate for several minutes.
Remass the pennies.
Tape the hollow penny into your lab notebook as proof of completion.
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.