# Determining the Percent of Copper and Zinc in Pennies

555 Words3 Pages
Determining the Percent of Copper and Zinc in Pennies Objective: * Find a way to measure the percent of density of the zinc and copper in pennies * Use best-fit straight line to examine linear relationships, and use it to create a predictive model to determine the percents * Learn to record lab data and observations, and practice with safe procedures in the lab. Background: As we know of today pennies are not made with just copper, they are made with many different metals and have a copper coating. To find the percent of copper you need to find the densities of the materials that make up a penny and then find the mass of just the copper and you can find a percent. Experiment Procedure: Determine the density of the following percentages of Zinc and Copper mixtures. Then compare the precision and accuracy of the data to the literature values for pre and post 1892 pennies when using various numbers of coins. Then determine the density of the coins. We will have to set up data sheetsin orders to record and calculate the data. 0% Cu, ~100% Zn 50% Cu, ~50% Zn 10% Cu, ~90% Zn 60% Cu, ~40% Zn 20% Cu, ~80% Zn 70% Cu, ~30% Zn 30% Cu, ~70% Zn 80% Cu, ~20% Zn 40% Cu, ~60% Zn 90% Cu, ~10% Zn Procedure: 1. Find the mass of the 5 dry pennies, then record the data. 2. Add 5 more pennies to the first group for the mass of 10 pennies, record mass. 3. Repeat step two, then continue adding 5 dry pennies each step to balance until you have used all 30 pennies 4. Fill Graduated cylinder with 20mL of distilled water 5. Drop 5 pennies (one at a time), into the graduated cylinder and record new volume 6. Repeat adding 5 pennies each time and record 7. Record Data in Notebook 8. Repeat steps with other set of 30 pennies Observations: I observed the copper’s density was greater than the Zinc. Anything with a higher based