6.03 Calorimetry Lab

Fill each cuvettes with its respective solution. Turn on the spectrophotometer, so it can warm up then calibrate it to 0% absorbance. Put the corresponding extract blank and set the spectrophotometer to 100% transmittance, then calibrate it to 540 nm. Once catechol is added in the cuvettes, make sure the solution is mixed. Place carrot cuvette in the spectrophotometer and record the resulting transmittance. Record the amount of absorbance by converting transmittance every 5 minutes for a total of 20 minutes. Repeat all of these steps for the cantaloupe, banana, replacing the blank each time to recalibrate the spectrophotometer. After recording all the percent transmittance value, the data was then converted into absorbance value by using the absorbance conversion table. The information was placed on a plotted graph

Connect the spectrometer to Labquest and select a new file. Calibrate the spectrometer by placing the blank inside and allowing the lamp to warm up. The optimal wavelength for the standard curve and data collection can be started at this stage. Empty the blank and use the solution from test tube one to rinse the cuvette twice. Fill it ¾ with solution one, wipe the outside, and place it in the spectrometer.

By determining the change in enthalpies for each step, we were able to add all of the individual enthalpies together to get the change in enthalpy for our goal reaction. The results can be seen in Figure 1. We were able to calculate qsol, qrxn, and ΔH using:

Cell membranes are the semi-permeable membrane that surrounds all cells. It separates the extracellular environment from the intercellular environment. It is a phospholipid bilayer which contains various proteins, lipids and carbohydrates all serving different purposes. It is this structure which allows for the transport of nutrients, proteins and water. (Nature.com, 2014). Through extensive testing it has been found that small alcohols, specifically ethanol can increase the fluidity and membrane permeability of the phospholipid bilayer (Patra et al, 2005). The aim of the experiment was to test what effect that ethanol solution would have on the membrane

Arginase is an enzyme- enzymes are biological catalyst which drives a reaction at the speed of life. Arginase is a hydrolase, hydrolases catalyze hydrolysis reactions, this is determined via the E.C number (Nelson and Cox 2008). Arginase has the EC number is 3.5.3.1 (Schomburg 2015). The enzyme ‘commission number’ is the arithmetical classification that is used for enzymes which indicates the chemical reaction they catalyze. EC 3 are hydrolases, which forms two products from the substrate via hydrolysis. (Bach, et al. 1961) This is seen in the equation: L- Arginine + H2OL-Ornithine + Urea (Nelson and Cox 2008).

Four randomly selected Daphnia magna, for each trial, were removed from the provided colony for the bioactive compounds to be tested, and were transferred with a plastic wide-mouth pipette with approximately 10 mL of pond water to protect and ensure survival of the Daphnia. In order to acclimatize the Daphnia to laboratory conditions, they were then placed onto a petri dish on the Daphnia cooling chamber. The cooling chamber was located on the stereomicroscope platform and brought down the heart rate of the Daphnia to a range that was countable by the observer, since Daphnia heart rate at room temperature is too rapid. On the cooling chamber there were two petri dishes: one for the Daphnia that were going to be tested, and one with the Daphnia being tested on, to ensure constant consistent temperatures for each trial. To maintain a temperature conducive to the heart

5. 150 ml of the solution in beaker A was added to the separating funnel with 10ml of chloroform. The funnel was gently shaken and vented to release the pressure. This was done five times.

In the lab, “Properties of Hydrates,” the purpose was to compare the properties of several well observable hydrates and to determine if dehydration is a reversible or irreversible change. The lab consisted of attaining a pea-size sample of each compound, burning it over a bunsen burner, and comparing the starting mass and the mass lost after the combustion. These results are important to be able to identify a variety of different chemicals that contain water molecules as part of their crystalline structure. Some can be removed by heating (resulting in evaporation) and some remain mostly unchanged. In this lab the answer will be found.

The pellets were dissolved thoroughly then was used in filling up the 100 mL volumetric flask. The solution was mixed well

First, a colorimeter and LabQuest were retrieved and and plugged in to warm up. While the colorimeter and LabQuest was warming up, 3 test tubes were labeled 1,2, and 3. Then, the control pH 7 solution was made according to Table 1 right in the corresponding test tubes. The test tubes were then immediately placed in a 100mL beaker with an ice cube in it to keep the solutions cold. The solution in test tube 1 was poured into a cuvette that was labeled with a piece of tape on the cap that said “B”. After the solution was poured in, the sides of the cuvette were wiped off with a Kimwipe to get rid of any fingerprints that could affect the colorimeter reading. The colorimeter was then set to the 470 nm setting, and then the “B” cuvette was

Titration process is used in an acid-base experiment in order to determine the concentrations of solutions of acids and bases. Through the titration process, we are able to identify physical changes to the mixture such as the colour change to indicate the end point of the experiment. For example, the colour changes of phenolphthalein from colourless to pink and methyl orange from red to orange and subsequently yellow. Acids produce hydrogen ions and bases produce hydroxide ions. This causes the indicator to change colour due to the colour difference from the undissociate molecules.

The term chromatography actually means colour writing, and signifies a technique by which the substance to be examined is placed in a vertical glass tube containing an adsorbent, the different segments of the substance traveling through the adsorbent at distinctive rates of velocity, according to their degree of attraction to it, and producing bands of colour at different levels of the adsorption column. The substances least absorbed emerge earliest; those more strongly absorbed emerge later. (Wixom et al., 2011)

Return the aqueous solution from the 500 ml beaker to the separatory funnel.  Add another fresh 40 ml of solvent to the funnel and again extract the aqueous solution as you did in b)

The final volume was adjusted with the same solvent to get concentration of 100 µg/ml. the solution was further diluted to get the concentration of 10 µg/ml, filtered through 0.45 µm filter tips , and aliquots of 20 µl from this solution was injected into HPLC by using an

In this study Calibration curve was plotted Concentration Vs Absorbance by preparing dilution between the ranges of 2?g/ml-12?g/ml. Absorbance was determined range ?between? 0.078 to 0.443.