1) Percentage yield experiment: First we measured 20cm3 of sulphuric acid into a beaker using a measuring cylinder, this will help us determine the percentage yield at the end of the experiment. We then heated the beaker containing the sulphuric acid using a Bunsen burner in order to heat it up for the copper oxide to mix with. We then weighed out 1.02g of copper oxide and added it to the acid and stirred it whilst doing so, we did that until the liquid turned blue, this proves that the chemicals have mixed together. We then weighed this liquid which will help us determine the percentage yield. We then filtered the liquid off which gave us the amount we obtained.
They were given the labels of “HCl”, “Na2S2O3”, and “water”, as was done to the beakers. The “water” syringe was then used to extract 2 mL of water from the “water” beaker. The syringe was examined to verify that no air bubbles were made in the syringe. The water was then translated into Well #3. Next, the “HCl” syringe was used, taking 1 mL of HCl from the “HCl” beaker, and then translated into Well #3 as well.
After 2.5 mL of NaOH had been added to the solution, the color of the solution remained blue for an acceptable amount of time. It was imperative for the experiment to be as fats as possible when performing this procedure, since there were times at which samples had to be collected. After completing this process the content of the Erlenmeyer falsk were disposed of in the halogenated waste container, and the Erlenmeyer flask was cleaned and prepared for the next steps. This same process of treating with acetone and titrating the solution was repeated at the 20, 35, and 50 minute mark, and the amounts of NaOH added to had to be recorded as well. Table 1.A was constructed in order to represent the resultant amounts of NaOH that were used and their respective time that they were added, as well as the amounts of sample and acetone that were mixed, and Calculations 1.A shows the calculations used to find the concentrations of HCl at different times, which is needed for the calculation of the rate constant.
Water will act as initial solvent for caffeine extraction. This is due to water that slowly soluble with caffeine at ambient temperature but highly soluble when temperature is at 100°C. Then, methylene chloride is chosen as the extraction solvent, due to its miscibility with caffeine and immiscibility with water. As mentioned above, the immiscible pair is chose for the extraction part because to allow the aqueous and organic layers to be separated. Basically, the bottom layer is the aqueous layer while the upper layer is the organic compound.
With the perfect conditions water boils at “212°F: Full rolling boil. ”(Lopez,K) Another factor in boiling point is any impurities residing the the water itself. “For instance, if water comes to a boil at exactly 100 degrees Celsius at 1 atmosphere, it means that is pure and does not contain any impurities. If the boiling point differs, it must mean that the water is impure.
Sodium carbonate, known for being found in soaps in glass, is soluble when mixed with water. When in its pure form, it is a white, odorless powder that can absorb moisture from the air (Sodium). On the other hand, calcium chloride can be used to melt ice on the roads, control dust, and act as a preservative for foods. It too rapidly absorbs water, but is a crystalline, lumpy or flaky texture that is usually white and quite soluble in water (Calcium). To understand this lab completely, it is important to know the concepts limiting and excess reactant.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
Next, is the verification and determination of pure liquids. A clean and dry a 25mL graduated cylinder must be gathered from the lab cart, weigh the dry cylinder to the nearest mg and record the data. Add distilled water to the cylinder making sure the water level is at above the 20mL mark but below the 25mL mark. Determine and record the temperature of the water in the cylinder. Then, reweigh the cylinder to the nearest milligram.
The acid was allowed to be poured for a little longer before the flask was removed and taken to a lab bench with a buret that contained 0.1 M sodium hydroxide, and the amount of acid used was recorded. The sodium hydroxide was added into the flask in small amounts
If it is affected, the experiment is not fair anymore. Size of beaker mL Using same volume of beakers To ensure that the diameter of the beakers are the same so that when same amount of hydrogen peroxide is poured into the beaker, the height of the solution would remain the same. As if the height changes, the distance the discs has to rise would change which would affect the time taken to reach to the surface.
The second step is about finding the theoretical yield, which will help to determine the correct amount of Ca(OH)2 can be made in chemical reaction. However, before doing this, it’s necessary to find whether CaCl2 or NaOH is a limiting reagent. For each test, the limiting reagent is found by multiplying the number of moles of the reactant by 1 mole of Ca(OH)2 and dividing then by a number of moles of reactant from the reaction. The lowest answer in each test will be the limiting reagent. To find a theoretical yield, the limiting reagent was multiplied by the molar mass of Ca(OH)2 and
The control in the experiment is water. Units used while timing the productivity of gas from an Alka-Seltzer tablet in different temperatures is, seconds. In order to find out if temperature controls the rate of chemical reaction, whether hot water is a more effective way to make the gas produce at a faster speed, it would be necessary to compare the results of different temperatures at the end of each trial. In order to do this the scientists will measure the volume of gas that is produced within a 10 second interval time after the tablet begins to react.
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.
Sodium hydroxide solution with a volume of 6.00 mL and a molarity of 3.00 M was transferred into a 50 mL beaker using a volumetric pipette. While swirling the phosphoric acid solution in the Erlenmeyer flask, the sodium hydroxide solution was added to it a few drops at a time using a disposable plastic pipette. The After all the sodium hydroxide was transferred, the flask was rinsed with 2 mL of deionized water and added to the flask with the reaction mixture and swirled for an additional minute. A clean, dry evaporating dish with a watch glass was then weighed and recorded to 0.001 g. The reaction mixture was then transferred to the evaporating dish.