Laboratory Preparation & Procedure

Materials:

• Copper cylinders
• Analytical balance
• Caliper
• 100-mL graduated cylinder
• Distilled water
• Unknown metal cylinder

Safety:

Handle metal cylinders with care. Do not drop metals into glassware.  Use calipers carefully as they can pinch fingers if misused. Never force them closed and keep your hands clear when measuring. Avoid spills around the balance.

Procedure:

1. Obtain a metal copper cylinder.
2. Zero your balance.
3. Place the copper cylinder on the balance pan and record the mass.
4. Measure the diameter & height of the copper cylinder using the caliper. Record each measurement to the correct precision of the device.
5. Determine the density of the copper cylinder using the volume by geometry measurement.
6. Using the actual density of the copper cylinder (8.92 g/cm³) calculate your percent error. *Note: Remeasure your copper cylinder if your percent error exceeds 5%. Add your density to the class data set at the front of the room.
7. Put enough water in the 100 mL graduated cylinder to cover the copper cylinder.
8. Record the initial volume of the water.
9. Carefully slide the metal cylinder down the side of the graduated cylinder into the water. Tossing it in can break the bottom of the graduated cylinder.
10. With the metal cylinder completely submerged, record the new volume reading.
11. Determine the volume of the metal cylinder using the volume by displacement measurement.
12. Using the actual density of the copper cylinder (8.92 g/cm³) calculate your percent error.
13. Obtain unknown metal cylinder. Record the identifying letter of the unknown metal cylinder the data section of this lab.
14. Zero your balance.
15. Place the unknown metal on the balance and record the mass.
16. Measure the diameter & height of the unknown metal using the caliper. Record each measurement.
17. Determine the density of the unknown metal cylinder using the volume by geometry measurement.
18. Put enough water in the 100 mL graduated cylinder to cover the unknown metal.
19. Record the initial volume of the water.
20. Carefully slide the unknown metal cylinder down the side of the graduated cylinder into the water. Tossing it in can break the bottom of the graduated cylinder.
21. With the unknown metal cylinder completely submerged, record the new volume reading.
22. Determine the volume of the metal cylinder using the volume by displacement measurement.
23. Use the chart below of known densities to identify your unknown.

24. Calculate the percent error between your calculated value and the theoretical density.