Determining The Density Of Unknown Metals Lab Report

Graphing to Determine the Density of Unknown Metals

Purpose: The purpose of this lab was to graph and compare measurements of mass, volume, and density of two unknown metals. Relationships in data and physical appearances were observed and used to identify each metal. The density was shown as the slope of the graph as both were equivalent to mass divided by volume. The experimental density was then compared to the actual value and a percent error was determined.

Materials: Equipment and materials used in this experiment were: unknown metal samples (2)

100 mL graduated cylinder electronic balance tap water wire screening weigh dish (Dixie cup)

Methods: The mass of five different amounts of an unknown metal sample was determined using an electronic

As shown in Data Table 1, the physical appearance of unknown metal #1 was a brown/orange color, a smooth surface, and the form of small round pellets, which are characteristics of copper. As shown in Graph 1, unknown metal #1 had an experimental density of 9.1924 g/cm3 which, of the given densities, was closest to the known density of copper (8.9 g/cm3 as found on the lab handout). The measurements had a 3.4% error as shown in calculations. The low percent error and the similar physical descriptions support the claim that unknown metal #1 was copper.

Unknown metal #2 was identified to be aluminum. As shown in Data Table 1, the physical appearance of unknown metal #2 was a dull, silver color, a smooth surface, and the form of large, rounded pellets, which are all features of aluminum. As shown in Graph 2, unknown metal #2 had an experimental density of 2.4484 g/cm3 which, of the given densities, was closest to the known density of aluminum (2.7 g/cm3 as found on the lab handout). The measurements had an 11% error as shown in calculations. The similar descriptions and low percent error support the claim that unknown metal #2 was

Relationships in data and physical appearances were observed and used to identify each metal. The density was shown as the slope of the graph as both were equivalent to mass divided by volume. The experimental density was then compared to the actual value and a percent error was determined.

Materials: Equipment and materials used in this experiment were: unknown metal samples (2)

100 mL graduated cylinder electronic balance tap water wire screening weigh dish (Dixie cup)

Methods: The mass of five different amounts of an unknown metal sample was determined using an electronic balance and a weigh dish. The volume of these five different amounts was determined using a 100 mL graduated cylinder and tap water through the method of water displacement. The water was poured into the sink using the wire screening to separate the metal from the water. This process was repeated for the second metal sample. The physical appearance, mass, and volume of each metal were recorded in data tables.

Results:

Data Table 1: Physical Appearance of Unknown