1. Describe the mechanism by which green fluorescent protein (GFP) is able to emit fluorescent light and why ultraviolet light is required to visualise it. (5 marks) When GFP is hit with UV light‚ the chromophore is hit by a photon. This changes the chromophore from ground state (A) to A*‚ which is a highly excitable state. Due to such a highly excitable state not being able to remain so for very long‚ the A* state chromophore emits a proton‚ lowering its state to I*‚ the energetic I. This I* state
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this experiment you will use calorimetry to measure the heats of reaction for three reactions: Reaction 1 Reaction Equation NaOH(s) → Na+(aq) + OH-(aq) Solid NaOH is dissolved in water 2 Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) → Na+(aq) + Cl-(aq) + H2O(l) Solutions of NaOH and HCl are mixed 3 NaOH(s) + H+(aq) + Cl-(aq) → Na+(aq) + Cl-(aq) + H2O(l) Solid NaOH is dissolved in a HCl solution The third reaction is actually a combination of the first two reactions. Notice that the equation for Reaction 3 can
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Indicator 1. Fill the 50-milliliter buret with a 0.25 molar NaOH solution. 2. Record volume. 3. Measure out between 20 milliliters and 40 milliliters of the unknown HCl solution. 4. Record volume. 5. The amount of unknown HCl is then added to the 100-milliliter Erlenmeyer flask. 6. Add two drops of the indicator‚ phenolphthalein‚ to the acid in the flask. 7. Using the slider on the right hand side‚ add NaOH to the HCl in the Erlenmeyer flask (This action is known astitrate). Add
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Volume of NaOH Required to Neutralize 10.00mL of Unknown HCl Molarity of NaOh | Trial 1 | Trial 2 | Trial 3 | Trial 4 | Initial Volume of NaOH(mL) | 0.00 | 11.00 | 20.85 | 30.45 | Final Volume of NaOH(mL) | 11.00 | 20.85 | 30.45 | 39.98 | Volume of NaOH used(mL) | 11.00 (Cancel out) | 9.85 | 9.60 | 9.53 | Average Volume of NaOH = (9.85+9.60+9.53)/3 = 9.66mL Sample Calculations: (9.85+9.60+9.53)/3 = 9.66mL The average volume of NaOH used. Calculations: 1. Moles NaOH = M x V = (0
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Standardization of a base (NaOH) using a primary standard (KHP) Standardization of an acid (HCL) with the standard base Titration analysis of unknown acids and bases (antacid tablets) Standardization of NaOH Materials: -Buret -250 mL Erlenmeyer flask -0.1 M NaOH -0.8 g KHP -Water -Three 150 mL beakers -magnetic stirrer A buret was rinsed with water and then with a small amount of the NaOH solution. Then the buret was filled with NaOH. The initial volume was read and
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Abstract: An experiment in which four amino acids‚ histidine‚ lysine‚ glutamine‚ and glutamic acid‚ are identified based on their titration behavior. Solutions of each unknown amino acid are made and the change in pH upon adding small amounts of NaOH aliquots of a strong base are monitored. The amino acids are identified using the information represented by the titration curves. The titration curves include the following information: isoelectric points‚ pKas‚ buffering regions and the structures
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balance and hot plate. Preparation of 250 mL 1.0 M sodium hydroxide solution (from solid) The amount of NaOH needed to prepare 1.0M solution was calculated (10.0 g NaOH). The computed value was weighed using the top-loading balance and placed in a clean and dry 250-mL beaker. Enough amount of distilled water to dissolve the NaOH solid was added to the beaker and stirred. After the NaOH was completely dissolved‚ the solution was then transferred to a 250-mL volumetric flask quantitatively. Enough
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result. Part A: Standardization of 2M NaOH(aq) Data Collection : Weight of substances Uncertainty Weight of watch glass + salt (potassium hydrogen phthalate) w1= 23.4380g ± 0.001g Weight of watch glass ( after emptying the salt)w2 = 21.5430g ± 0.001g Weight of salt (potassium hydrogen phthalate) w1 –w2= (23.4380± 0.001g) – (21.5430g ± .001g) = 1.8950± 0.002g Titration Table - Volume of distilled water Burette Reading NaOH/ml Volume of NaOH solution for neutralization End point
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mL of 0.862M HCl. It was added to the empty coffee cup calorimeter‚ and its initial temperature was obtained by using the MeasureNet. Using a graduated cylinder‚ 50 mL of 0.901M NaOH was added into the cup‚ and the final temperature was obtained. The solution was disposed‚ and the coffee cup calorimeter was rinsed with distilled water. The next experiments were performed. The acid was always added before the base. Experiment 2 consisted of 100 mL of 0.862M HCl and 100 mL of 0.901M NaOH. Experiment
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Diagram 13C: N/A Observation 13G: Mass of NaOH = 10.836g Table 1:oxalic acid Calculated mass of oxalic acid dihydrate 3.150g Mass of weigh boat (g) .500g Mass of weigh boat + oxalic acid (g) 3.662g Mass of oxalic acid (g) 3.162g Concentration of 100.00ml .2510M Table 2: NaOH Mass of NaOH + weigh boat 11.336g Mass of weigh boat .500g Calculated mass of NaOH 10.836g Moles of NaOH .2709mol Concentration of 500.0ml NaOH .5418M Table 3: HCl Volume of Concentrated HCl 10.00mL Concentration diluted to 250
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