What is the advantage of using max wavelength rather than the wavelength nearby such as 580 nm?

This is for the Bradford protein assay where the maximum of the absorbance spectrum is at 595 nm.

When 2.3 g Co(NO3)2 is dissolved in 0.375 L of 0.44 M KOH, what are [Co2+], [Co(OH)42- ], and [OH- ]??? (Kf of Co(OH)42- = 5.0 109)

1. In preparation of common alum, why is it necessary to reduce the volume of your reaction mixture after the addition of sulfuric acid?

2. What was the whitish material that formed in the filter flask liquid after you began washing your product?

3. What was the purpose of washing your product with either ice-cold water or alcohol?

4. Why must the oven temperature be kept below 100 C when drying your product? (Two Reasons)

For the reaction 3O2(g) + 4NO(g)-->2N2O5(g)

the rate of change in concentration of O2, delta[O2]/deltat = 0.057 mol/L.sec. What is the rate of change of NO and what is the rate of change of N2O5? Show your calculations.

Compare the binding isotherm of normal hemoglobin (at pH 7.4, with 7.8 mM 2,3 BPG) with that of the following variations. For each variant, clearly explain why or why not the binding isotherm changes the way it does.

Explain Please!

a) Hemoglobin at pH 6.9, 7.8 mM 2,3 BPG

b) Hemoglobin in which a glutamate residue (at a position normally exposed to the solvent) has been substituted for a valine residue (at pH 7.4, with 7.8 mM 2,3 BPG)

c) Hemoglobin at pH 7.4 with 9.4 mM 2,3 BPG

d) Hemoglobin with a mutation in the beta chain position 94 (position FG1) (at pH 7.4, with 7.8 mM 2,3 BPG). In this mutation Asp94 ->His.

Calculate delta H rxn (at 500K) for the formation of 1 mol of ammonia gas. (show worked out solution)

When heated, ammonium carbonate decomposes as follows: NH4CO2NH2(s) ⇌ 2NH3(g) + CO2(g). At a certain temperature the equilibrium constant is K_P = 2.9 x 10^-3. Calculate the total equilibrium pressure at this temperature.

If the pH of a 1.00-in. rainfall over 1800miles2 is 3.40, how many kilograms of sulfuric acid, H2SO4, are present, assuming that it is the only acid contributing to the pH?

For sulfuric acid, Ka1 is very large and Ka2 is 0.012.

What is the effect of the following changes on the volume of 1 mol of an ideal gas? (Note: You should NOT need to do any explicit numerical calculations. Use your qualitative understanding of how volume depends on different experimental variables.)

1. The pressure is changed from 0.5 atm to 760 mm Hg (at constant temperature).

2. Another 3 mol of gas (to the existing one mol) is introduced through a stopcock (at constant temperature and pressure).

3. The pressure is halved and the temperature is changed from 0 °C to 546 K.

4. Another 1 mol of gas is introduced and the pressure is changed from 380 torr to 1 atm (at constant temperature).

5. The temperature is changed from -173 °C to 200 K (at constant pressure).

The answers are: the volumn quadrupled/doubled/halved/stays the same

Discuss the effect of (a) cholesterol addition, (b) free fatty acid addition, and (c) lysophospholipid addition to a membrane bilayer. Be sure to include an explanation of concentration dependence in biochemical and physical terms. Will your answers to (b) or (c) change if you consider saturated versus unsaturated fatty acids?

Aspartate transcarbamoylase (ATCase) catalyzes the first step in the biosynthesis of a nucleotide. The end product of the pathway, cytidine 5’-triphosphate (CTP), in turn inhibits ATCase activity. This effect can be overcome by the addition of ATP.

a) Sketch the enzyme activity curve of ATCase alone, ATCase + CTP, & ATCase + ATP. Explain your rationale.

b) The regulation of ATCase activity by CTP exemplifies what TWO types of regulation?

5.0 g of iron is reacted with 5.0g of water according to the chemical equation shown below. 3 Fe(s) + 4 H2O(l) → Fe3O4(s) + 4 H2(g)

a) Calculate the amount of Fe3O4 produced, in grams.

b) What is the mass of excess reagent, in grams?

1. Write out the balanced equation for the oxidation of hydrobromic acid by hydrogen peroxide.
2. How many stereoisomers of stilbene dibromide can exist?
3. A possible definition of a meso compound is: “while possessing 2 or more assignable
stereocenters, a meso compound is superimposable (identical to) its mirror image in at least
one conformation”. In other words, it is identical to its would-be enantiomer except for the fact
that the molecule contains… what? What physical characteristic arises in meso compounds
that results in the above definition?
4. Let us assume a cut-and-dry, black-and-white case that the mechanism does only one of 2
things when each molecule of product is produced: (1) goes entirely bromonium-ion/antiaddition;
or (2) goes through a fully-fledged planar carbocation intermediate with absolutely
no selectivity.
a. If you were to find by quantitative analysis that exactly 50% of your product mixture
was the meso stilbene dibromide and the other 50% was racemic stilbene dibromide,
then is mechanism case (1) or (2) favored? If so, qualitatively, by how much?
b. Think again. Question (a) is a mind-bender. I want to know what you originally /
immediately thought, and what you eventually came to. If they are not different, you
are either a genius or need to think more. Write out all the possibilities…
c. If you find, qualitatively, that >95% of the product is meso, what does this imply about
the mechanism? What percent of the time does the mechanism go by scenario (1)…
greater than what number?
5. Describe a more likely blend of mechanisms that could have produced your estimated product
distribution

Nevermind