Unknown Metal Lab Report

In chemistry, elements have properties that distinguish them from one another. Despite the various chemical properties, one of the most important physical properties is a property known as density. Density was first discovered in 250 BC by the Greek mathematician Archimedes when he compared real and fake gold by placing both in water. The key principle is that density will affect whether objects float or sink. If an object has a higher density than its surroundings, it will sink. Inversely, if an object has a lower density than its surroundings, it will float. Archimedes also found that regardless of size or shape, a given element will always have the same density. With this discovery, density today is represented as the measure of mass per

This was achieved by using physical observations, logic, and mathematical calculations. In order to do this efficiently, several answer choices were given for the unknown metals. These choices were Bismuth, Manganese, Copper, Lead, Zinc, Tin, Cobalt, Nickel, Cadmium, and Chromium. For the unknown metal in this case (sample #21), the density was approximately 6.848g/cm3. This alone however, is not enough information to identify the metal. Based on observations, the unknown metal was very dark and black in color, as well as flaky in terms of texture and shape. Because it was clearly observed that the unknown metal was black in color, several of the possible choices can be eliminated. To reduce error, it is critical to eliminate choices carefully and with confidence. Copper can be eliminated because of its red hue, while cobalt is not a possible match due to its blue color. Bismuth can also be eliminated since it contains a variety of colors, and so this element cannot be the match because as previously stated, the unknown metal was only black in color. Moving one step forward, the remaining choices are Manganese, Aluminum, Lead, Zinc, Tin, Nickel, Cadmium, and Chromium. At this point, the density can be used to classify since a few of the choices have been removed. Approximately at 25 degrees Celsius, Manganese has a density of 7.44, Aluminum with 2.70, Lead is at 11.35, 7.13 for Zinc, 7.31 for Tin, 8.91 for Nickel, 8.65 for Cadmium, and 7.19 for Chromium, where all of the densities have a unit of g/cm3. Based on information from the experiment sheet, it is affirmed that the calculated density of the unknown metal should be accurate to about 0.1%, although eliminating options based on this would not be reasonable, as lab data is not necessarily consistent every time. On top of density, logic and reasoning can also be used. To demonstrate how logic and reasoning can be