Determining the Density of a Solid and Liquid

1. Determination of the Density of Liquid Ethanol

1. Place a clean and dry 50-mL volumetric flask on an analytical balance.
2. Press the “Tare” or “Zero” button on the balance. The balance should read 0.000 g.
3. Use a buret funnel to add 45 mL of liquid ethanol to the volumetric flask.
4. Use a Pasteur pipette to add the final 5 mL of liquid, just until the bottom of the liquid’s meniscus touches the marking on the flask.
5. Weigh the volumetric flask again and record the mass of the ethanol.
6. For best results, repeat steps 1.1 – 1.5 twice more to obtain two additional density measurements.

2. Determination of the Density of Solid Zinc Metal

1. Add approximately 40 mL of water to a clean and dry 100-mL graduated cylinder. Record the exact volume of the water.
2. Place the cylinder and water on an analytical balance. Press the “Tare” or “Zero” button on the balance. The balance should read 0.000 g.
3. Add approximately 10 zinc pellets to the graduated cylinder. Record the new volume of the water plus zinc pellets using the liquid level after addition of the zinc (Figure 1).
   
   Figure 1. Zinc added to the cylinder on the right causes the water level to be displaced upward.
4. Weigh the cylinder, water, and zinc pellets on the balance. Record the mass of the zinc pellets.
5. For best results, repeat steps 2.1 – 2.4 twice more to obtain two additional density measurements.