You are removing imidazole from your pooled nickel column samples by dialysis. The
volume of the pooled sample is 32 mL and the imidazole concentration is 0.5 M.

a. What is the concentration of imidazole after exposure to three consecutive dialyses
against 1 L of buffer?
b. If the imidazole at the start is 3.4% (w/v), what is the concentration in
weight percent at the end of the dialysis (three consecutive exposures to one liter
of buffer)?

Predict the effect on each of the following if the product was not completely dried after the recrystallization:
(a) percent yield; (b) melting point; (c) IR spectrum.

importance of discussion in study

Using 1.0 nM enzyme X for the enzyme kinetics experiments, you obtained the reaction rates at different concentrations of substrate (shown in the following table). Assume that the enzyme X follows a typical Michaelis-Menten kinetics.

[substrate] (μM) Reaction rate (μmol/s)

2 7

5 17

10 29

20 44

50 67

100 80

200 89

500 95

1000 98

a) Estimate the Vmax and Km values of the enzyme X in this reaction using the double reciprocal plot.

b) If 5.0 nM of the enzyme X is used in the experiment, what will be the Vmax and Km values of the enzyme X?

Rank the following from highest to lowest boiling point

1. 0.18 m NH4CH3COO

2. 0.14 m Cr(CH3COO)2

3. 0.13 m CuBr2

4. 0.45 m Urea(nonelectrolyte)

Absorbance at 540 nm of Bromocresol Purple Dilution Series

1. The point 0/0 is an important and valid point on this graph. Why? (Explain)  Explain how a hand-drawn graph and excel graph are similar or different.

2. How is the Beer’s Law equation similar to that of a straight line? Explain each component using the letter of the component and using a set of your experimental values. BCP: 0.015M

3. Evaluate your data using the Beer’s Law equation: use the absorbance reading for the highest concentration of a solution, determine the extinction coefficient for the BCP solution you were given. Do you get the same answer if you make this calculation at another concentration?

4. Select 2 random absorbance readings on your line (that you did not actually measure) and explain two different ways you can use your graph to determine the concentration of BCP (µg/mL) of the unknown solutions that might have the selected absorbance values.  ***Provide the results; what values do you determine to be the concentrations of your 2 random absorbance readings?

5. Explain why we refer to a graph such as the one you just constructed as a “standard      curve” or a “calibration curve.” How would a graph such as this one be useful?

Methane is burning with minimum amount of air to form the stable products. The premixed methane-air mixture is filled in a leak-proof spherical vessel at an initial pressure of 1 bar and 298 K. The vessel is well insulated to avoid thermal energy interaction with the surroundings.The combustible mixture is ignited at the centre of the vessel using an electrical spark. The energy added to the mixture for ignition is negligible. During the combustion process, the pressure of the combustion chamber increased due to the energy released by the fuel. Estimate the peak pressure that is achieved inside the vessel at the end of complete combustion without any dissociation of products. Both the reactants and products are in gas phase.

PleaseI need the procedure on how to solve this questions!

Thanks!

Consider the reaction at 298 K
SO2(g) + 2H2S(g) ? 3S(s) + 2H2O (g)

The ?G

A gas mixture with a total pressure of 770 mmHg contains each of the following gases at the indicated partial pressures: 133 mmHg CO2, 233 mmHg Ar, and 183 mmHg O2. The mixture also contains helium gas.What is the partial pressure of the helium gas?

A coffee cup calorimeter contains 480.0 g of water at 25.0 ^oC. To it are added:
380.0 g of water at 53.5 ^oC
525.0 g of water at 65.5 ^oC

Assuming the heat absorbed by the styrofoam is negligible, calculate the expected final temperature. The specific heat of water is 4.184 J g^–1 K^–1.

Select one:

a. 38.2 ^oC

b. 48.2 ^oC

c. 67.6 ^oC

d. 88.7 ^oC

Consider the tripodal molecule, NH3, under C3v point group constraints. Derive a 12 x 12 matrix for the transformational matrix of the C3 rotation axis

One of the most popular methods for determine trace amounts of water is a coulometric titration, called the Karl Fischer. Measuring trace amounts of water is one of the most challenging analytical methods.

a) What would be another method that would measure larger amounts of water contained in a sample, and how would you do it?

b) The Karl Fischer method is a secondary coulometric analysis that utilizies the generation of I2/I3 with starch, just like you did in lab, generated from the Iodide ion. This iodine molecular species then reacts with water in a complicated Redox, involving stinky pyridine....hense, the advantage of doing this by remote control under a hood. The actual limiting reagent is WATER: One mole of water reacts with one mole of generated I3.

The goal of your problem is to find the ppm of water in a 250 mL sample of pure ethanol, that has a density of 0.7893 g/mL. A current of 55.5 milliamps was run for 4 minutes 23 seconds, until the blue/black color of the starch was observed. However, the current generator box was only 89.3 % current efficient, losing some current. The electrochemical production of the tri-iodide ion reagent was the same oxidation reaction as in lab. What is the ppm of WATER contamination the 250 mL of pure ethanol?

Questions asked after completing quantitative volumetric analysis of pickling vinegar & NaOH (regular vinegar consists 5% acetic acid, CH3COOH. Piclking vinegar consists 7% of the acid).

1. Is there a trend in the values obtained in class? (there was a trend) Explain.

2. If regular vinegar costs $1.00/L & pickling vinegar costs $1.25/L, which is the best by? (i.e use a logical argument to determine which gives you the most acetic acid for your dollar)

3. Why do we only include the trials that agree withing 1% of each other? What is the difference between accuracy & precision for a series of measurements?

4. Identify 4 important sources of systematic (not human) error. Discuss why they are important.

5. If 0.25M potassium hydroxide solution was used as the titrant, instead of 0.1 M NaOH (aq), would your titration have use dmore or less itrant to reach the end point? Use a logical argument to determine how much more or less titrant would be required.

Given the following reactions of nitrosyl chloride (NOCl), calculate the ∆H°rxn, in kilojoules per mole, for the third reaction. Enter your answer to the tenths place. Don’t forget the sign! 2NOCl(g) ⟶ 2NO(g) + Cl2 (g) ΔHrxn ° = +79.2 kJ mol ⁄

NOCl(g) + 1 2 O2 (g) ⟶ NO2Cl(g) ΔHrxn ° = -39.1 kJ mol ⁄

2NO(g) + Cl2 (g) + O2 (g) ⟶ 2NO2Cl(g)