Calorimetry Lab Report

 Determination of % Composition of Pennies Using Redox and Double Displacement (Precipitation) Reactions Introduction: Oxidation involves the gain of electrons of hydrogen or the loss of oxygen or decrease in oxidation state. If zinc completely reacts with HCL, then the theoretical yield of copper should be equivalent to the actual yield. Purpose: In

Elena Chen CH 221-227 November 3rd, 2009 Lab Report #3: Copper Cycle Abstract: The purpose of the experiment is to cycle solid copper through a series of five reactions. At different stages of the cycle, copper was present in different forms. First reaction involves reaction between the copper and nitric acid, and copper changed from elemental state to an aqueous. The second reaction converted the aqueous Cu2+ into the solid copper (2) hydroxide. In the third reaction Cu(OH)2 decomposed into copper 2 oxide and water when heated. When solid CuO reacted with sulfuric acid, the copper returned to solution as an ion (Cu2+). The cycle of reactions was completed with the reaction where elemental copper was regenerated by Zn and Cu

|Experimental stage |Observations | |1. Copper metal (penny) at the start |Tarnished, worn out, brownish, copper-colored, fine solid. |

Abstract. An unknown blue copper (#32) was measured by iodometry with sodium thiosulfate. The procedure from the lab handout Iodometric Determination of Copper was followed. The thiosulfate was standardized by titrating KIO3 with starch in acidic conditions to produce triiodide. Starch is the indicator for iodine having the appearance of a blue complex; starch was added before the endpoint in order for the endpoint to be sharp since there is low concentration of iodine. After the thiosulfate was standardized, the unknown copper titration was performed. Sodium acetate was added to the copper analyte before titration to increase the pH to 3. The pH is raised to 3 because a low pH would produce extra triiodide, and a high pH would produce

The 2012 penny was held, with tongs, in the hottest part of the bunsen burner. The penny turned uniformly gold. After the penny was rinsed with cold water, measurements were taken on the 2012 penny. The 2012 penny, which was gold, had a thickness of 0.11 centimeters. The mass of the “gold” penny was 2.46 grams, with the diameter being 1.89 centimeters. Looking at the results, the 2012 penny was the least thick of the group. In addition, the 2012 penny was more heavy than the 1985 (copper) penny, but less heavy compared to the 1984 (silver)

Chemistry, an age old science that to this day were are still developing and advancing, was once based off the concept of alchemy, where scientists attempted to turn common metals like lead and copper into precious ones like gold. These experiments were regarded as magic tricks, with experiments The preparation of Gold we got to see behind the curtains of their act. For the experiment we would be attempting to turn common copper pennies into gold, testing whether or not the transformation is possible. My hypothesis is that the pennies won't turn into gold, as that is impossible, but a copper alloy of some sort. An alloy is a mixture of two or more metals, or a metal and nonmetal, which is heated and mixed together. The substance probably has

The wire reacted with the solution to yield copper; any remaining aluminum was dissolved with a few drops of 6M HNO3. Following the isolation of the copper, it was separated from the solution with a Büchner funnel and flask. A piece of filter paper was weighed, and its mass was recorded. Then, the filter paper was placed on the vacuum flask, which was turned on, and the copper solution was poured over it. The copper was also rinsed with 95% ethanol solution before being set on a paper towel to dry. Finally, one day after the previous step, the copper was weighed, and its mass recorded. The recorded masses were then used to determine the mass of copper, chlorine, and water in the unknown copper chloride hydrate. The resulting masses were used to find the formula of the unknown copper chloride hydrate according to CuxCly•nH2O.

The Alternating Chemical Reactions of the Copper Cycle *Nikko Baez and John Harling Chemistry 111 Course Section 475 Introduction: Copper has a very important biological and environmental significance, and is considered one of the most important elements all over the world. Within this experiment, copper’s ionic and elemental forms will be examined. This will be done by exposing copper to a series of chemicals and transforming copper into a nitrate, a hydroxide, an oxide, a sulfate, and then changing it back to its original element, copper. This process is known as the Copper Cycle, and can be used to study and observe the different types of chemical reactions that exist within our biological and environmental systems.

Creating Solutions of Standard Molarity Madelene Andersson Sarah Toadvine CHEM 1251L-013 10/13/2014 Introduction: The purpose of this lab is to find the unknown concentration of Cu+2 by comparing the solution to a set of standard concentrations, different known concentrations, which are prepared by diluting approximately 2.5 grams of copper (II) sulfate pentahydrate. A concentration is the amount of solute relative to the volume of a solution, the more solute the more concentrated the solution will be. Concentrations are reported using molarity (M) which is the moles of the solute by the volume of solution in liters.

To analyze the product and confirm its molecular identity, infrared spectroscopy and proton NMR spectroscopy were conducted. The H1NMR produced a spectra (Figure 5) which was consistent with the predicted chemical shift from the hypothesized product. The presence of a multiplet centered on the 7 ppm region is

Figure 3. shows the plots of 1/ƛ vs. 1/ n 2 of hydrogen. This plots shows the slope of hydrogen. Table 1. and Table 2. Show the emission spectrum lines for hydrogen and helium.

In part A, According to AA, the thickness of this layer is less than .03 mu (Szczepankiewicz “et al., 1995). -brass appears silver, but brass will appears golden. When the penny containing -brass is heated, it converts into -brass, a golden color. The reason is probably due to the penny being expose to oxygen, which results in a chemical change. Since this experiment used sodium hydroxide, the net reaction in this experiment was . Assuming if penny 1 was cut in half, the center would contain mostly solid zinc and a tiny amount of cupper. The most out layer would be the brass. Like penny 1, the outer layer of penny 1 will contain brass. However, the center layer would contain mostly copper. This method to plate zinc on other metal works, but only if the half reaction of zinc is above the metal. Zinc will not deposit on solid cadmium because the half reaction of cadmium is above of zinc on a standard electrode potential table, which means Zinc will be

With a given 10x20 Whatman #1 chromatography paper, the dots were marked and numbered from 1 to 9 in pencil within 2 cm intervals from each edge, 2 cm along the lines, and 2 cm from the bottom. With a scrap piece of chromatography paper, 8 substances were obtained; Red #3 (erythrosine), Red #40 (Allura red), Blue #1 (brilliant blue FCF or erioglaucine), Yellow #5 (tartrazine), Red food coloring, blue food coloring, green food coloring, and yellow food coloring. And the last ninth substance was needed to made with brown M & Ms. The 2 brown M & Ms were left on the beaker mixed with 0.5 mL water and 0.5 mL ethanol. Once the brown color disappeared from shells of the M & Ms to the solvent, the liquid changed from clear to dark brown color.

Introduction Scientific Background Concepts The determination of the amount of copper in a penny involves multiple scientific concepts that are extremely important. First, the experiment involves a redox reaction of Copper and Zinc. Copper and zinc are both components of a penny and the oxidation reaction utilizes nitric acid, a very strong oxidizing agent, in order to oxidize both copper and zinc. The reaction generates a highly toxic, brown gas which is nitrogen dioxide (NO2), but more importantly, it results in the complex ions of copper and zinc. The complex ion generated of copper is Cu(H2O)42+ and has a dark blue hue while the complex ion generated of zinc is Zn(H2O)42+ and does not have a distinctive color. Essentially, a complex ion is formed by having a central metal ion that has formed covalent bonds with multiple ligands, which are simply anions. Furthermore, the Beer-Lambert Law establishes a relationship between light absorption and solution concentration by claiming that the concentration of a certain solution is directly proportionate to the total amount of light energy that the compound present in the solution can absorb (The Beer-Lambert). A spectrophotometer can be utilized to measure how much light energy of a certain chosen wavelength is absorbed by a particular sample.

The first source of error that could have occurred in this experiment relates to the decanting process for which we were starting to separate the newly produced copper from the solution. Even when carefully pouring the mixture of deionized water and the solution into the sink, loose copper particles, most