Moles of Zinc Are in a Penny

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How many moles of zinc are in a penny? Purpose: this lab is being performed so students can visualize a single-replacement reaction and calculate how much zinc is in a post-1982 penny? Materials: A post- 1982 penny steel wool 3 M HCl graduated cylinder Small beaker tongs Balance paper towels Sharp edge Safety: 3 M hydrochloric acid (HCl) is fairly caustic. Wash hands immediately is you spill on them. Wear goggles. Procedure: 1. Clean off penny with steel wool 2. Use a file and cut a small groove into four edges of the penny. Opposite sides works well. 4. Mass the penny and record it. 5. Place the penny in 20mL of M HCl that is in a small beaker. 6. If you use the tongs, PLEASE wash them because the acid will continue to react with them overnight. 7. Let the penny sit overnight. If you do not see bubbles, something is wrong. Write down your observations. 8. After the penny is finished reacting, using the tongs, remove the penny. 9. Wash off the penny in tap water carefully and thoroughly. You will be holding the pennies with your fingers and if you still have acid in or on them, it can be uncomfortable. 10. Dry off the penny carefully. 11. Mass the penny again and record. 12. Calculate how much zinc left the penny. Calculations: 1. How much zinc left the penny? Mass of penny before M HCl: 2.47g Mass of penny after: -1.66g = .81g of zinc left the penny. 2. What is the class average for amount of zinc in a penny. (* means not included in average.) Class data: (in grams) *.81 *.75 2.3 *1.72 *1.39 2.37 2.06 *1.03 2.02 2.18 2.3+2.06+2.02+2.37+2.18=10.93 10.93/5= 2.186 Class average mass of zinc in a penny is 2.19g 3. How much (in g) of the penny was made of copper? Mass of penny 2.47g Mass of zinc - .81g =

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