Calorimetry Of Reaction Lab Report

CaCl2 and 5 mL water, 2 tsp. CaCl2 and 2 tsp. CaCl2.The question asked at the beginning of the lab was what chemical must be present for a color change to occur. My hypothesis was that if Phenol red was present then a color change would occur. This hypothesis was true because every reaction that had phenol red experienced a dramatic color change while the other reactions did not.

Introduction: The copper content of U.S. pennies has declined over the years due to rising prices. The expensive metal makes up just 2.5 percent of one-cent pieces minted in 1982 or later; nickels, dimes and quarters, on the other hand, are mainly composed of copper. Still, today’s pennies cost more than their face value—an estimated 1.8 cents each—to produce.

Next we moved the beaker into the fume hood where we added the nitric acid, HNO3(aq), where the solution started to fizzle and there was a brown gas produced called nitrogen dioxide, NO2(g), which then made the solution blue called copper nitrate, Cu(NO3)2(aq), which smelled like bleach. When we put the 25 mL of water nothing happened to the solution and looked the solution looked the same. After, we had to measure 2 mL of the concentrated sodium hydroxide, NaOH(aq), in the graduated cylinder and then poured into the beaker slowly which made the solution a darker blue and made it a solid copper hydroxide, Cu(OH)2(s). When the beaker was placed onto the hot plate the solution was turning black and into a solid that smelled bad called copper oxide, CuO(s). When it cooled down nothing happened but when the mixture was being filtered the solids stayed in the filter paper and a clear liquid came out which was sodium nitrate, NaNO3(aq).

In this reaction NaOH was added to the Cu(NO3)2. The solution developed a precipitate which made the clear solution become cloudy and uniform in color (blue). The physical color change was demonstrated through the formation of the precipitate. The third step was the formation of CuO. In this reaction, the Cu(OH)2 product was heated on a hot plate and stirred continuously until the solution became colorless and a dark precipitate formed.

The solubility rate of copper (II) chloride in methanol is 53g/100ml whilst the solubility rate for sodium chloride is 65g/ml. Although there solubility rate is fairly close the difference is enough that when little amounts of methanol is added only the copper (II) chloride dissolves. A factor that affects the solubilty of metals is their molecular mass. Copper (II) has a molecular mass of 63.546 whilst sodium has a molecular mass of 22.989769 meaning copper has higher solubility rate than sodium, this is because as the molecular mass of a metal increases it becomes difficult for molecules to hold onto their solute particles and when those particles break away they can easily dissolve into the solvent. Therefore because coppers molecular mass is greater than sodiums it’s solute particles breakaway with less resistant meaning copper dissolves better.

Before starting the heating process, measure the weight of the crucible with its cover first and then tare the balance, and after that adding about 1 gram of the sample to the crucible with its cover, and then weigh it. Moreover, it is possible liberating harmful gases during the process of heating; therefore, being careful is important. The heating process ends when this sample changes the color to brown because water of hydration is removed to the sample. Additionally, give time to the small cool down and measure its weight. Next, transfer the sample to a 50 mL beaker and mixes with distilled water, which gets by rinsing the crucible with its cover in 8mL, so the solution is generated.

Introduction Heat is the form of energy, thermal energy, which flows between two substances due to their difference in temperature.1 The measurement of heat flow is called Calorimetry and the apparatus used to measure the heat flow (temperature change) for a reacting system is called a calorimeter. The calorimeter is well-insulated device that help to minimize the heat exchange between the system being observed and its surroundings. In this experiment, simple calorimeter, coffer cup calorimeter containing Styrofoam cups is used. Calorimeter contains a thermometer and a stirrer.3 Thermometer is typically inserted in the calorimeter to measure the change in the temperature that results from the reaction.

The final product is a blue liquid. There are many principles that are demonstrated by this experiment.

At 120 drops of NaOH the mixture turned very bright blue and the drop of the solution on the red litmus paper turned the paper blue as well, indicating the reaction was

Glacial acetic acid and acetic anhydride were added to the mixture while refluxing, which converted the lime colored solution into a clear mixture. The flask was cooled in an ice bath and the solution

Weighed 1 gram of NaC2H3O2 and mixed it with ionized water. Boiled 12 mL of 1.0M Acetic Acid added into a beaker containing the sodium carbonate on a hot plate until all the liquid is evaporated

The observed emission data for the different elements did not look how they were supposed to. However the “peaks” for Hydrogen were found to be 534.52 and 631.24, 534.70 and 569.11 for Helium and 529.73 and 630.71 for Mercury. The Rydberg’s Constant found to 1.1x107 8.5x104 while the known constant is 10967758.34m-1. The percent error of 0.29% and the accuracy of this reading is 99.7. The slope and intercept of the linear regression line is -0.01 3.3x10-5 and 0.02x10-1 1.9x10-6 respectfully.

In this graph the results is about what we expected, which is a big amount of heat given off. In observing the graph the distance between reaction 1 and reaction 2 shows the total amount of heat given off which is the combination of 1&2 in comparison to room temperature that the water was originally at. Through the experiment there was a lot of question as to if we were doing it right, were we swirling the solution around enough, did we open the top right so heat would not escape, did we collect the data at the right time? Now looking back I see that many of the things that our group did defiantly altered our data, making me question the reliability of the data we collected. The first reaction was CaCO3(s) + 2HCL(aq)------- CaCl2(aq) + H20(l) + CO2(g) and the second reaction that was given was Ca(OH)2(s) + 2HCl(aq)-------CaCl2(aq) + 2H2o(l) combined gave off about 57 degrees Celsius going into a system (Calomitery and Hess’s Law).

(NH4)2CO3 was added to the solution. Then the tube was placed into warm water. Once the tube was cooled, the tube was centrifuged and 0.5 mL of 6M acetic acid was added to the precipitate. This was done to see if the precipitate turned cloudy. The solution was clear and not cloudy.

Based on the R2 values from your graphs, do you think that density trends on the periodic table are linear relationships? What rationale could you offer to explain your answer? The R2 value established from the group 4 graph demonstrates a linear relationship with a steady increase. The period IV graph provided a very low value of R² = 0.0028 on the linear trendline and presents nearly any correlation at all.