6.03 Calorimetry Lab

In this experiment an elemental copper was cycled a series of five reactions where it ended with pure elemental copper as well, but at different stages of the cycle the copper was in different forms. In the first reaction, elemental copper was reacted with concentrated nitric acid where copper changed the form from solid to aqueous. Second reaction then converted the aqueous Cu2+ into the solid copper II hydroxide (Cu(OH)2) through reaction with sodium hydroxide. The third reaction takes advantage of the fact that Cu(OH)2 is thermally unstable. When heated, Cu(OH)2 decomposes (breaks down into smaller substances) into copper II oxide and water. When the solid CuO is reacted with sulfuric acid, the copper is returned to solution as an ion (Cu2+). The cycle of reactions is completed with the

Washing of the copper is necessary in this experiment to separate the iron from the copper and make sure the iron is not counted in the mass of the copper.

The Cu Later lab experiment is designed to allow you to practice lab skills in implementing and performing a series of reactions. Specifically, four types of chemical reactions will occur: oxidation/reduction; double replacement; single replacement; and decomposition. You will begin with a known amount of copper metal, which, after progressing through several steps, is reproduced. In this experiment you will observe and record the various changes such as heat, color changes, and production that occur. This procedure is used to observe some chemical reactions of copper and its compounds while also performing the lab appropriately as to retain the copper as much as

Put approximately 9-10(g) copper ore into beaker. Use spatula to break up any large pieces. Next add 17ml H2SO4 (aq) (hydro sulfuric acid) to the beaker. Began mixing until all or most traces of blue dissipate; or the copper ore will no longer dissolve (should appear as a milky liquid). Next use pipette to and remove solution and divide solution into 2 individual test tubes then Place test tubes into centrifuge and run centrifuge for 1 minute. Remove from centrifuge machine Fill a cuvette with the clear solution from the test tube making sure not to disturb the sediment at the bottom. Note the solution should bluish in tint Final place the cuvette in the colorimeter. Then record data and calculate in results section.

1. In the human blood, there is the bicarbonate buffer system. CO2 is released from cellular respiration and then taken up by red blood cells. Next, it is changed to carbonic acid which dissociates to form bicarbonate and H+ ions.

The initial magnesium had a mass of 0.06 g while the final compound had a mass of 0.08 g. Magnesium oxide had been formed, and no magnesium should have been lost over the process due to magnesium being unable to form gases or liquids with any of the elements it had been exposed to.

Introduction: The purpose of this lab was to learn the proper techniques of roasting, smelting, and volumetric analysis to determine an unknown sample of copper mineral.

The purpose of Step 8 is to make sure we get the exact mass of the solution. There could be trapped molecules of water in the solution. Heating the solution would evaporate the water molecules.

The understanding of oxidation and reduction must be clear to carry out this lab. With the understanding of these concepts we can calculate or hypothesize for the properties of each element or compound. 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.

Before the synthesis of the Copper Iodine Compound, the identities provided (CuNO3)2 and Nal weighed 1.65 g and 4.7 g, respectively. After being weighed, the (CuNO3)2 exhibited a blue color, while the Nal, through observation, was a white color. However, when both identities were combined, the product turned into a brown and red rocky material. Once 20 mL of deionized water was added, the product quickly turned pale pink paste. After the solution was repeatedly washed with a total of an additional 100 mL of deionized water, the product was powdery and pink with small grains, and was left to air-dry. Once the product was air dried, it was observed to be a pale pink color, while the filter paper was stiff as the product was hard and dry. Therefore, the solid was scraped off onto a recrystallizing dish. However, the mass of an empty recrystallizing dish needed to be recorded in order to compare how much of the synthesized copper iodide was obtained. Within this case, the empty recrystallizing dish used weighed 32.01 g, the product on the empty dish weighed 1.03 g, having a total weight of 33.04 g.

The lab performed required the use of quantitative and analytical analysis along with limiting reagent analysis. The reaction of Copper (II) Sulfate, CuSO4, mass of 7.0015g with 2.0095g Fe or iron powder produced a solid precipitate of copper while the solution remained the blue color. Through this the appropriate reaction had to be determined out of the two possibilities. Through the use of a vacuum filtration system the mass of Cu was found to be 2.1726g which meant that through limiting reagent analysis Fe was determined to be the limiting reagent and the chemical reaction was determined to be as following:-

In this experiment, the mass percentage of water, and the molecular formula, of a hydrated copper (II) sulfate will be calculated through an understanding of hydrates, percent composition, and moles.

This lab was to see chemical reactions with different liquids. This was important to find the unknown substance. The controlled variable was the unknown powder, since it doesn’t change. The independent variable was the liquids. These liquids were vinegar, iodine, and water. Lastly, the dependent variable is the chemical reactions. The reaction was affected by the different liquids. If the liquids are changed then the chemical reactions will be different, because they have different properties, causing the atoms to bond differently.

This experiment shows in detail how copper goes through different stages and exists in various compounds before being recycled back to its pure state. Each reaction associate with each step of the copper cycle was done in order to produce the next stage of the copper life cycle. The experiment also provided a good insight into how the reactions functioned by analyzing what each of the five reactions were: reduction, oxidation, acid-base, decomposition, or precipitation. The final amount of pure copper that recovered after the experiment was finished to determine the if the initial and final amounts were close by calculating percent recovered and relating that amount to supporting or refuting the Law of Conservation of Mass that applies to the Copper

In the second part of the experiment, we obtained copper wire and sulfur from the instructor. Then we measured out the mass of copper and added proper amount of sulfur to cover the copper wire. During the lab, copper with sulfur was heated, and the reaction was carried out. We saw the blue flame occurred on the crucible. We determined the empirical formula of copper sulfide, which was Cu2S. Then, the equation was balanced easily from the obtained data which was 2Cu + S = Cu2S.