Percent Yield Lab Report

Post Lab Questions: 2Mg + O2 →2MgO 0.29gMg 1molMg24.312molMgO2molMg100= 4.40molMgO ←theoretical yield 2Mg + O2 → 2MgO →2/24 =

Hence in the sample only copper (II) chloride will dissolve leaving the sodium chloride behind once filtered through. The copper (II) chloride can then be obtained by evaporating the methanol; which has a boiling point of 65 degrees celsius whilst copper (II) chloride has a boiling point of 993 degrees celsius, thus allowing the methanol to be easily evaporated out of the solution eliminating concerns of the copper (II) chloride evaporating alongside the methanol. Purpose To investigate different methods of separating copper (II) chloride and sodium chloride in order to obtain the original masses of both substances.

Major unknown #202 was given out by the instructor, and the unknown bacterium was streaked out on a Trypticase Soy Agar tube and plate to inoculating the bacterium and incubating. After incubated and grown the morphology was observed and several Gram stains were performed to determinate if the bacterium were gram positive or negative, and the morphology of the bacterium. The Gram Stain of my major unknown #202 was determinate to be Gram negative bacilli, and was double checked by the Gram check slide. Also I noticed that my bacterium was a facultative anaerobe and according to my results of endospore test, my bacterium has not endospores. So according to the list of possible major unknowns provided by the instructor, I narrow my bacterium thru

As seen in table 1, the theoretical yield was .712 g of C_17 H_19 NO_3. The % yield of this experiment was 7.51 % of C_17 H_19 NO_3. . This low yield can be explained from a poor recrystallization technique combined with potential contamination. Throughout the experiment, the mixture changed color from green, orange, to yellowish lime, and eventually clear.

Purpose: The purpose of this lab is to find the percent composition of sugar in gum, and how it differs based on the brand of gum, by using the percent by mass. Hypothesis: If two separate brands of gum are masticated, in which is based on Trident and Orbit Gum, then the mass of the sugar/ the percent composition of the sugar in the gum would be the same, because the amount of sugar and sugar alcohol used in the gum are the same, based on the nutritional facts provided. Variables: Independent Variable: The Brand of Gum Dependent Variable: Percent of Composition of Sugar in Gum / Mass of Sugar (in g) Controlled Variables: The Amount Sticks of Gum, The Flavor of the Gum, Materials: ~

The percent recovery of the copper was calculated using the equation, percent recovery = (the mass of the copper recovered after all the chemical reactions/the initial mass of the copper) x 100. The amount of copper that was recovered was 0.32 grams and the initial mass of the copper was 0.46 grams. Using the equation, (0.32 grams/0.46 grams) x 100 equaled 69.56%. The amount of copper recovered was slightly over two-thirds of the initial amount.

(150.22g/mol)(3.5 x 10^-3 mol of nucleophile) = 0.525 g Actual yield = 0.441 g, Percent Yield = (0.441g/0.525g) x 100% = 84% 10. Percent recovery from recrystallization = (0.172g/0.441g) x 100% = 38% 11.

The objectives of this experiment were to use knowledge of chemical formulas and chemical nomenclature to experimentally determine the empirical formula of copper chloride. Common laboratory techniques were used to conduct a reaction between copper chloride and solid aluminum in order to get rid of the water of hydration. The amount of water of hydration in the sample of copper chloride hydrate was calculated by measuring the mass before and after heating the sample. Afterwards, an oxidation-reduction reaction was conducted, resulting in elemental copper.

The percent yield was 22.33%. In most cases, that means that a lot of possible product was lost. However, in this case, that was not true. When Benzaldehyde reacted with the Wittig reagent, it produced two products: E-Stilbene and Z-Stilbene. The Z product was a liquid, while the E product was a solid.

One error that could have affected the percent yield is not filtering out all of the liquid from the filter paper in the funnel before setting it off to dry. This would have increased the final mass of the solid, not making it accurate. To stop this from happening again, the liquid could be drained more thoroughly until it fully stops dripping into the Erlenmeyer flask. Another error that could have affected the percent yield is the amount of trials performed. This would have made the results less accurate and made any errors change the final results even more.

After the reaction is finished, the percentage composition of each element in the product can be found and used to calculate the empirical formula, which is the lowest whole number ratio

The weight of 2-methyl-2-butene recovered was 1.056 grams, so in finding percent yield I divided the two: (1.056)/(1.4) x 100 = 75.4%. For the second part of the experiment we used .20 moles of KOt-Bu and 0.02 moles of 2-methyl-2-bromobutane, again making 2-bromo-2-methylbutane the limiting reagent. In calculating the theoretical yield: (0.02 moles)(70.13 g/mol) = 1.4 grams. The weight of the major product (2-methyl-1-butene) recovered was 1.299 grams, making the percent yield: (1.299)/(1.4) x 100 =

⋅ 5H2O, which has about 36.0%, and CuCl2 ⋅5H20 (21.17%). Materials: Ring stand, ring clamp, evaporating dish, Bunsen burner, clay triangle, crucible tongs, electronic balance, sample of hydrated salt. Methods:

World refined copper usage has been increasing since 1900 continuously from less than 500 thousand tons to 22.9 million metric tons in 2014 with an annual rate of 3.4% (ICSG, 2015). Of course the growth rate of increase in consumption slowed down during the years of global crisis. Given the fact that world population is slightly over 7 billion and the current cooper consumption in the world is around 22.9 million tons, the per capita consumption of copper is approximately 3,27 kg making it world’s third most important metal (in terms of weight) after iron and aluminum respectively. On the production side, the leader country for mine production is Chile with almost one-third of the world production whereas for the refined production it is China with again approximately one-third of the world production (ICSG, 2015). As the share of production and economic growth of Asian countries has been increasing, their copper needs also increase due to the rise in production of industrial equipment manufacture together with rise of building construction.

Joshua Miller 12/18/17 Fermentation Lab report Introduction The term fermentation refers to the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat (wikipedia). Sugars are converted to ethyl alcohol when fermentation happens. In this experiment we determined if yeast cells undergo fermentation when placed in a closed flask with no oxygen. Glucose and yeast are mixed together in a closed flask and allowed to incubate for about one hour.