Lab Report On Chemistry Lab

At five minute intervals over the next fifteen minute period, record the color intensity of the solution of each test tube.

7. Tape the strip to a pencil and rest the pencil on top of the jar so that the strip hangs into the jar. The goal is to have the end of the chromatography strip just touching the surface of the solvent solution, with the colored dots above the surface of the liquid. Make sure that the colored spots do not come in direct contact with the liquid in the bottom of the glass.

Four test tubes were labeled “H2O A”, “H2O B”, “Enz A”, and “Enz B”. In the test tubes labeled “Enz A” and “Enz B” 1 mL of catalase was pipetted into each, and in the test tubes labeled “H2O A” and “H2O B” 6mL of deionized water was pipetted into each. Next the two test tubes labeled A were placed into an ice bucket, and the test tubes labeled B were placed in a 50°C water bath. These were left in their respected locations for 5 minutes each, and then the temperature of the test tubes in the ice bucket were recorded. Next the “Enz A” test tube was mixed with the “H2O A” test tube and 100µL of guaiacol and 150µL of .1% H2O2 were added to this mixture using a micropipette. The test tube was then covered with aluminum foil and inverted to mix the solution and then placed in a curvette and into the spectrometer. The initial absorbance was recorded and the curvette was placed back in the ice bucket. Then the contents of the test tubes labeled B were mixed and 100µL of guaiacol and 150µL of .1% H2O2 were added to this mixture using a micropipette. This was then placed in a curvette and into the spectrometer and the initial absorbance was recorded and the curvette placed back in the water bath. Finally after 5 minutes of time had passed each of these were placed in the spectrometer again and their absorbance levels recorded. This process should be a very quick one to ensure that the

10 microliters of the sample is then added and the assay absorption is measured at 340nm. If absorbance was above 1.5, samples were diluted.

3.0g of salicylic acid was weighed then 3.0mL of acetic anhydride and 6 drops of 85% H3PO4 were added to it. The mixture was warmed over a water bath for 5 minutes while stirring. After warming, 20 drops of distilled water was slowly added. 15mL of water was added then the solution was heated until it became clear. It was allowed to cool and was placed in an ice bath until the solution becomes cloudy. Using pre-weighed filter paper, the mixture was filtered and was allowed to dry in the filter paper.

each  anion solution into  a centrifuge tube.   The tubes  were labeled accordingly.  The original color of

A Mohr pipette allowed for the accurate measuring of a standard solution, by recording the final and initial pipette readings of 0.200 M Fe(NO3)3 and 0.00200 M KSCN. With Le Chatlier’s principle in mind, an excess of 0.200 M Fe(NO3)3 was used rather than 0.00200 M as a flooding technique to keep Fe(NO3)3 constant throughout the reaction and favor the products. To determine the equilibrium solutions, four 50 ml beakers were obtained by recording their final, initial, and total volume dispensed. Beaker 1 consisted of 5 ml Fe(NO3)3, 2 ml KSCN, and 3 ml H2O. Beaker 2 contained 5 ml Fe(NO3)3, 3 ml KSCN, and 2 ml H2O. Beaker 3 consisted of 5 ml Fe(NO3)3, 4 ml KSCN, and l ml H2O. Lastly, beaker 4 contained 5 ml Fe(NO3)3 and 5 ml KSCN. Next, the absorbance values were calculated by placing each solution into a 470 nm colorimeter, then using Logger Pro to determine the absorbance for each solution when given the concentration values. As seen in table 3, the absorbance value for the standard solution was 0.818 with a [Fe(SCN)2+] concentration of 2.00  10-4 M. To reduce error, Mohr pipette readings were recorded to two decimal places and data was not recorded on the meniscus of the line. This allowed for a higher quality of recordings and the avoidance of biased

On a thin chromatography plate, five spots were placed ( as shown in table 2) and the plate was developed using chloroform/methanol. This was later visualized with dragendorff’s reagent under the UV light. All separated components were observed, identified and recorded.

Parafilm was used to avoid spillage of the solutions in the test tubes. Test tubes were gently inverted every two minutes to create a well-mixed solution because the chelating agents eventually settled. xi. After 10 minutes the catechol was added to test tubes 1-4 and the blank tube was used to calibrate the spectrophotometer. Test tubes were read one after the other after the blank tube, and the transmittance of light was measured and recorded in a

The chemical compounds that were used to make the solutions in this part of the experiment are: Tin (II) Chloride, Hydrochloric acid, and Sodium Chloride. The new solutions that were made had values that were given in a table in the Laboratory Manual. Similar steps were performed in this part of the experiment that were also performed in the first part. The solutions were put into cuvettes, that were then put into the colorimeter machine, which displayed the absorbance, transmittance, and time values. After this information was collected it was put into an Excel spreadsheet and a graph of the time versus absorbance was generated.

The spectrophotometer was used to measure the concentration of compounds in a solution according to the amount of light that passes through the solution. We warmed up the spectrophotometer for about 10 minutes and set the wavelength at 540 nm. Five test tubes were prepared each containing a different amount of catechol, water and substrate concentration. Tube one contained 1.0 mL of Buffer, pH 6.0 0.1 M NaPO4 including 0.1 mL of 0.006 M catechol, with 150 uM of substrate concentration and 1.9 mL of distilled water. Tube two contained 1.0 mL of Buffer, pH 6.0 0.1 M NaPO4 including 0.2 mL of 0.006 M catechol, with 300 uM of substrate concentration and 1.8 mL of distilled water.

During the first part of the experiment a dot of ink was placed onto chromatography paper to separate the mixture by pigment. This chromatography paper was place so that a portion of the paper below the dot was in water, so that the water could travel up the paper and separate the ink. The paper was suspended using a toothpick that was put through the top of the paper, which was held by the neck of the bottle.

My aim for this experiment is to find out how different types of solvent will affect the retention factor in paper chromatography.

A series of experiments were carried out in which the concentration of iodide ions is varied while keeping the concentrations of all the other solutions the same. In each experiment, the time taken for the colour change is recorded. The results obtained are used to determine the rate of reaction. The rate of reaction can be represented as (1/time) and the concentration of the iodide ions can be represented by the volume of potassium iodide solution used.

The chromatography paper has to be gently handled by the edges. Then a 2 cm line is made from the bottom point of the paper using a ruler and pencil. The pencil line must be covered by the leaf and then pressed into each other (along the line) using the edge of a quarter. It must be repeated until a dark line appears and also thin as possible. The chromatography paper is inserted into a test tube that contains 5ml chromatography solvent, the pigment and pencil lines are adjusted to be above the solvent. Then the test tube must be recapped and placed in the hood. Meanwhile, the solvent is being observed to see if it moves upward on the paper and if the pigments appear one by one. Since the solvent is not allowed to reach the top of the paper, as it comes near the top it must be removed quickly from the test tube and a pencil line must be drawn to mark the leading edge, also the solvent front, because the solvent evaporates quickly. Each band color is numbered, lowest band number being 1. The center of each color band is estimated and marked. Then the distance is measured by the initial pencil line to the center of t he band. Each pigment is determined by the given colors: (reddish purple = anthocyanins, yellow-green = chlorophyll b, blue-green = chlorophyll a, yellow = xanthophylls, yellow = B carotene). The distance the solvent moved must be measured using this formula