Composition of a Post-1983 Penny Lab Report
Through the use of percent composition one can easily find out how much of a certain element is in a compound or an item such as a post-1983 penny. The experiment will be using HCl a strong acid to dissolve all the zinc inside the outer copper shell. The reaction follows as such; Zn+2HCLZnCl2+H2, but there will be no reaction with copper. The portion that will be measured is the mass of copper left after all of the Zn goes through the reaction process. Hypothesis:
If the penny is post-1983, then there will be a percent yield of copper greater than 30%. Research Question:
What is the percent composition of Copper and Zinc in a post-1983 penny? Aim:
The purpose is to determine the percent composition of Zinc and Copper metals in a post-1983 penny with the use of HCl. Variables:
Independent Variable: percent composition of Zinc.
Dependent Variable: percent composition of Copper.
Controlled Variable: Molarity of HCl, and year of penny.
Beaker Penny Goggles HCl Filler Distilled Water Method:
Note that HCl is an acid and must be cautious around this acid for it can burn your eyes so wear goggles, and wash hands after the lab. 1. Retrieve a penny that is post 1983, and clean and dry the beaker you are going to use to make sure it has no residue from any previous users. 2. Fill 3 slots into a copper about 1/3 of the way or till you see the gray portion. (Note it will be more effective if each filling mark is at 120o angle of each other.) 3. Once the penny has been filed, weigh it and record its mass. 4. Weight the...