The experiment was on the density of the metals: Copper, Zinc, and a mystery metal. The mystery metal was discovered to be Aluminum. The density of Copper and Zinc were taken so the percentages of how much of both went into making a penny. Through careful experimenting and math the deduction was made that 87% of the penny was Zinc and the other 13% was Copper.
The purpose of this lab was to do three things: 1. To calculate the density of three metals: Copper, Zinc, and a Mystery Metal.
2. To identify the unknown metal. 3. To calculate the percentage composition of an ordinary penny.
To discover the percentages, finding the density was a good place to start. The density is the mass divided by the volume of the object or "the mass per unit of volume" (Kingdom 35). Density is important in determining a substance's identity because many elements have different densities.
For example, Radium has a density of 5.0 not many elements have a density of 5.0 (Periodic). The only loop hole for this explanation to density's importance is the densities of Cobalt and Iron, both of which are 7.874. An alloy is "the mingling of the regions of the Isthmus, mixing chromium, manganese, nickel, or cobalt into iron to form the designer metals of the current age." (Kingdom 128-129). For example a common penny is an alloy mixing copper and zinc to create the 1 cent piece we see today. A significant figure is "The number of digits in a measured or calculated value that gives meaningful information about the thing being measured or calculated" (Idiot 353). A percent error is used to say how much of an error there was in the test that was done. Percent error is calculated be taking the...