Materials and Methods The experiment used Potassium permanganate (KMnO4), a purple substance; Potassium dichromate (K2Cr2O7), a yellow substance; and Methylene Blue, a blue substance. These substances have molecular weights, 158 g/mole, 294 g/mole and 374 g/mole. A petri dish containing agar-water gel with three wells was obtained as shown in Figure 1. Each well was labelled as potassium permanganate, potassium dichromate and methylene blue. One drop of every prepared substance was carefully placed into its respective wells in the agar-water gel using a dropper. The petri dish was immediately covered to avoid the possible effects of other foreign factors. The substances, each having specific colors, spread in the agar-water gel as shown in
figure 2. The diameters (mm) of the colored area were measured by a 12-inch commercial ruler at 3-minute interval from zero to thirty minutes. The outcomes were recorded in Table 1. To determine the average rate of diffusion, the partial rates of diffusion were calculated using the formula: Partial rate (rp¬) = di - di-1 ti - ti-1 where: di = diameter of colored area at a given time di-1 = diameter of colored area immediately before di ti = time when di was measured ti-1 = time immediately before ti The partial rates of diffusion and the average diffusion of each substance were recorded in Table 2.
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
The purpose for this experiment was to determine why it was not possible to obtain a high percent yield when Calcium Nitrate Ca(〖NO_3)〗_2 with a concentration of 0.101 M was mixed with Potassium Iodate KIO_3 with concentration of 0.100 M at varying volumes yielding Calcium Iodate precipitate and Potassium Nitrate. Filtration was used to filter the precipitates of the solutions. The percent yield for solution 1 was 87.7%, and the percent yield for solution 2 was 70.8%. It was not possible to obtain a high percent yield because Calcium Iodate is not completely soluble and some of the precipitates might have been rinsed back to the filtrates when ethanol was used to remove water molecules in the precipitate.
The unknown bacterium that was handed out by the professor labeled “E19” was an irregular and raised shaped bacteria with a smooth texture and it had a white creamy color. The slant growth pattern was filiform and there was a turbid growth in the broth. After all the tests were complete and the results were compared the unknown bacterium was defined as Shigella sonnei. The results that narrowed it down the most were the gram stain, the lactose fermentation test, the citrate utilization test and the indole test. The results for each of the tests performed are listed in Table 1.1 below.
All things, living or nonliving, consist of atoms and molecules. These particles are constantly in motion, and this continuous motion allows for the disbursement of molecules, or diffusion. The overall net movement of these molecules will go from areas of higher concentration, to areas of lower concentration. Therefore, following a concentration gradient (Martini). The rate of diffusion of these molecules, in accordance with Fick’s law of diffusion, is directly proportional to the concentration gradient present. However, the concentration gradient is not static and will change over time and with distance, therefore changing the rate of diffusion. It is hypothesized that the two solutions being tested, Methylene Blue and Potassium Permanganate, will begin their initial diffusion in the agar gel at a quick rate, and then progressively regress over the allotted time of 1 hour. Another factors other that will have an effect on rate of diffusion is molecular size. There is a substantial difference in molecular weight between Methylene Blue (320 g/mol) and Potassium Permanganate (158 g/mol). The combined molecules present in Potassium Permanganate are lighter than those in Methylene Blue, and therefore should allow it to diffuse more rapidly.
K2CrO4 was added to the solution in order to create a solution with Ca2+ cations because CaCrO4 is completely soluble, and was dissolved in the solution, while BaCrO4 is insoluble. The resulting orange solution with possible Ca2+ ions was decanted. A yellow precipitate was observed, which could have indicated the presence of barium in the form of barium chromate, a yellow salt. However, this was proven to be a false positive, a test which incorrectly confirms the presence of a substance, when the presence of calcium ions was confirmed by the precipitation of CaC2O4, a white precipitate, in step 14. In this case, the presence of barium was incorrectly confirmed by the false positive. The observed yellow precipitate was formed due to the reaction of leftover lead ions from part A with potassium chromate, to produce lead chromate, which is also a yellow precipitate. While this observation was unusual, it was expected, especially since lead had been confirmed in part A, making the occurrence of the false positive more likely. The various chemical equations for part B were as
The advantage of mini-cycle for the glucose metabolism will be less consuming time to produce glucose 6 phosphate because oxaloacetate can be produced rapidly from alpha-ketoglutarate. If there is deficiency of glucose 6 phosphates, the body can use mini-cycle to produce it by converting oxaloacetate (278). The disadvantage will always need enough oxygen to process this reaction because mini-cycle is aerobic metabolism (304). For the fatty acid metabolism, citrate can produce rapidly from alpha-ketoglutarate instead of using long general pathway of TCA cycle. When citrate is produced from oxaloacetate and acetyl-CoA in mitochondria, it will transfer to cytoplasm when beta-oxidation is suppressed. Then, citrate will convert into acetyl-CoA and oxaloacetate.
In this lab, solutions were separated by polarity and affinity to solids by chromatography. Chromatography is the separation of a mixture, where the components move at different rates up a medium. The medium used was chromatography paper, matched with a series of developers to aid in movement of compounds upwards. The distance moved up the paper is measured and the rf is calculated. The distance the pigments traveled is divided by the distance developer traveled. The more polar a substance the further it travels up the paper. The paper works by capillary action and absorption to separate the compounds.
Purpose: Collect the experimental data necessary to construct a solubility curve for potassium nitrate (KNO3) in water.
1. First I took five test tubes and filled each one with 5ml of black, blue, green, red and ‘clear’ colouring (for the ‘clear’ colouring I simply used water.)
The composition of water in magnesium sulphate pentahydrate using measured values is 46.0% water and 54.0% magnesium sulphate. The composition using defined values is 51.12% water and 48.83% magnesium sulphate. The hypothesis for the value of x was 6, and the experiment conducted also resulted in the value of 6 for the number of water moles to magnesium sulphate. However, the hydrated salt has 7 moles of water to 1 mole of magnesium sulphate, creating magnesium sulphate heptahydrate. This shows that there were experimental errors when conducting the experiment. One of the possible reasons why the calculations resulted in a different number was due to the hygroscopic nature of magnesium sulphate. As it is hygroscopic, the ionic compound continuously
In 1807, a man by the name Sir Humphrey Davy discovered Potassium in London, England (Barbalance, Environmental-Chemistry). Potassium was the first element to be found through electrolysis (Softschools). Electrolysis is the chemical decomposition produced by passing an electric current through a liquid or solution containing ions. In addition to electrolysis, thermal methods are also used to produce potassium. Thermal method is a mixture or a reactant that I measured as a function of temperature or time while the sample is subjected to a controlled temperature program. Potassium Is a pure element, but it can also be found in mixtures. Potassium, however, is a silvery-grey metal formerly named Kalium hence the symbol K.
The second experiment was done by using the substances potassium permanganate (KMnO_4), potassium dichromate (K_2 Cr_2 O_7), and methylene blue having a partial diffusion rates of 0.36 mm/min, 0.33 mm/min and 0.33 mm/min, respectively which means potassium permanganate which has a molecular weight of 158 g/mole, has covered more in terms of diameter than potassium dichromate and methylene blue which have a larger molecular weight.
The diffusion rates of potassium permanganate, KMnO4 (MW: 158 g/mole), potassium dichromate, K2Cr2O7 (MW: 294 g/mole), and methylene blue (MW: 379 g/mole) were compared and observed on an agar-water gel. An amount of each of the three substances was dropped on the wells of the gel. The diffusion rates were recorded by measuring the diameters of the substances at a regular three-minute interval for thirty minutes. Potassium permanganate had the biggest diameter after 30 minutes. Methylene blue had the smallest diameter. Thus, the molar weight of a substance highly affects its diffusion rate.
This method was found by Karl Friedrich Mohr in year 1856 9. Chlorides are titrated with silver nitrate solution in the presence of chromate anions. End point is physically observed by presence red silver chromate precipitate. Initial signs of red silver chromate precipitate is hard to detect due to the intense yellow colour of chromate. Positive error will occur is concentration of the titrant is less than 0.1M. Determination of blank could be performed to avoid this error. Blank is done by titrating solution of indicator potassium chromate with standard silver nitrate solution. Chemical reaction equation is showed;
1gm of powdered sample is taken in a Kjeldhal digestion flask and 5ml of NaOH solution, 1gram of Davardas alloy is added. In another flask 2% of 20ml boric acid is prepared and kept below the Kjeldhal flask. The mixture is digested in fume chamber for about 2 hours till the sample from the Kjeldhal flask condenses and approximately 200ml of distillate is collected in the boric acid beaker. The contents are then diluted with distilled water up to the mark in a standard volumetric flask. The distillate (25ml) is then titrated with 0.02N HCl using methyl orange indicator till the color changes from yellow to orange red and the burette reading is noted down.