Calorimetry Lab Report

1. 100 + 273 K = 373 K 150 + 273 K = 423 K 960 L x 423 K / 373 K = 1,089 L 2.

This labs objective was to determine how much copper is in a penny. Concepts that were used for this lab were calibration curves, and oxidatoin of metal.

The purpose of this lab is to figure out the mass percentage of copper in a penny. Furthermore, by doing this lab we will practice using a spectrophotometer and review the names of equipment such as volumetric glassware, pipets, and volumetric flasks.

The purpose of this experiment was to find, compare, and contrast the mass, volume, and densities of copper and zinc pennies. Information about the pennies was acquired before the start of the lab. The pre-lab research stated that any pennies that were minted before 1982 are composed of pure copper, while any pennies after 1982 are made out of zinc. The densities of copper -- 8.96 grams per centimeters cubed -- and zinc -- 7.13 grams per centimeters cubed -- were also information that was acquired before starting the experiment. With knowing the density of the two metals, this hypothesis was formed: If the mass and volume of pennies made out of zinc and copper are both measured, then the copper pennies will have a greater mass, because copper has a greater density than zinc. This hypothesis was formed because density equals mass over volume and if the mass is greater in an object that has the same volume, then the density of the object will be greater than the other.

In this lab, we will determine the percent composition of a modern (post-1982) penny by using a strong acid to react and dissolve the zinc core, leaving only the copper coating. Once only copper remains, we will compare its mass to the entire mass of the penny to determine how much of a penny is copper and how much is zinc.

The Copper Cycle is a popular experiment used to determine if an element, in this instance, copper, reverts to its elemental form after a chain of reactions. This experiment is very dangerous because of the reactions between the strong acids and bases. In this experiment I performed a series of reactions starting with copper metal and nitric acid to form copper (II) nitrate. Then I reacted copper and several other solutions such as, sodium hydroxide, sulfuric acid, ammonium hydroxide, and hydrochloric acid to form precipitates. In conclusion my percent recovery

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 approach: In the first reaction, copper metal turnings oxidize when put in contact with nitric acid and become copper nitrate.

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.

When comparing the 1970s penny and the 2010s penny, one discovers that the 1970s penny has more copper in it because the 1970s penny is denser than the 2010s penny. Although the measurements of the pennies were very close, there were several factors that may have caused them to be incorrect such as the caliper not clamping completely, the engravings on both sides of the pennies,

Table 2: Summary of data collected on concentration of mercury in surface water samples of Onondaga Lake in 1992 (NYSDEC/TAMS, 2002)

Calorimetry is the science of measuring the change in heat absorbed or released during a chemical reaction. The change in heat can tell us if the reaction is either exothermic - it released or heat into surroundings, or endothermic - it absorbed heat from surroundings. The device used to measure calorimetry is a calorimeter. A calorimeter can range from very expensive lab ones to coffee styrofoam cups but they are all tightly sealed in order to prevent heat from escaping.

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

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

We did this experiment to investigate about turning copper into gold. We did this experiment to find out that whether adding heat and chemical can change a substance’s colour. To find that out, we placed the pennies into the hot zinc powder and sodium hydroxide solution and added heat flames to the penny. After this experiment, we found out that adding certain chemicals and heat can change the colour of a penny from copper to silver to gold.