Outline the mechanism of the conversion of α-ketoglutarate to succinyl-CoA catalyzed by α-ketoglutarate dehydrogenase complex.

Put these 5 steps in order:

1. decarboxylation

2. transacylation

3. dihydrolipoyl dehydrogenase activity

4. oxidation of 4-carbon group, reduction of lipoamide disulfide

5. enzymatical FADH2 reoxydation by NAD+

Aqueous solutions containing approximately 3 percent(w/w) H2O2 are sold in drug stores as a disinfectant. Determination of the actual concentration of H2O2 in a bottle of peroxide solution was done by diluting 1.00 mL to 100 mL with water, acidifying with dilute H2SO4 and titrating with a 0.01231 M KMnO4 solution. If 41.92 mL of the permangate solution was needed to reach the end point of the titration, what is the actual molar concentration of the H2O2 solution? Hint: Balance the reaction first: MnO4 - + H2O2 -> Mn2+ + O2 using half reactions

For main-group elements, are outer electron configurations similar or different within a group? Within a period? Explain.

A water is in equilibrium with CO2 in the atmosphere (partial pressure is 3.16 .10‾⁴atm) and with CaCO3(s). The pH is 8.1. Ignoring Ca complexes, what is the
solubility (S) of Ca?

Match the following aqueous solutions with the appropriate letter from the column on the right. 1. 0.14 m Al(NO3)3 A. Lowest freezing point 2. 0.17 m Cr(CH3COO)2 B. Second lowest freezing point 3. 0.18 m (NH4)2CO3 C. Third lowest freezing point 4. 0.48 m Sucrose(nonelectrolyte) D. Highest freezing point

Calculate the pH of a buffer solution that is obtained when 1.727 mL of 3.0 M HCl are added to a 48.273 mL of aqueous solution in which 0.727 g of Tris base has been dissolved. The allowed error is 0.02 pH units.

In Part B of the experiment you uses a weak base, sodium bicarbonate to completely convert a weak acid to a salt. Why was sodium bicarbonate able to completely convert the acid whereas many weak bases would have left some unreacted acid because of the equilibrium?

2. Balance the first redox reaction in acidic solution and the second redox reaction in basic solution.

S + NO3- → SO2 + NO

Cr2O72- + Fe2+ -----> Cr3+ + Fe3+

Determine the Vmax and the Km of the enzyme in the absence and presence of each inhibitor. Calculate the KI for each inhibitor. Are the inhibitors all the same? Which is the best inhibitor and why? What is the catalytic efficiency and turnover number of the enzyme knowing that during the experiments its concentration was 2 nM? What happens to the catalytic efficiency and turnover number of the enzyme in the presence of each of the inhibitor?

The following velocity data were obtained for an enzymatic reaction in the absence and presence of three different inhibitors (A, B, and C):

Initial velocity (v) Initial velocity (v) Initial velocity (v) Initial Velocity (v)

[S] Control (no inhibitor) (+A at 6μM) (+B at 30μM) (+C at 4mM)

(mM) (nM/min) (nM/min) (nM/min) (nM/min)

0.200 16.67 6.25 5.56 10.00

0.250 20.00 7.69 6.67 11.11

0.333 24.98 10.00 8.33 12.50

0.500 33.33 14.29 11.11 14.29

1.00 50.00 25.00 16.67 16.67

2.00 66.67 40.00 22.22 18.18

2.50 71.40 45.45 23.81 18.52

3.33 76.92 52.63 25.64 18.87

4.00 80.00 57.14 26.67 19.00

5.00 83.33 62.50 27.77 19.23

Given the data:

PbO(s), D_f H^q = -217.3 kJ mol^–1, S^q = +68.7 J mol^–1 K^–1
PbO₂(s), D_f H^q = -277.0 kJ mol^–1, S^q = +68.6 J mol^–1 K^–1
O₂(g), D_f H^q= 0.00 kJ mol^–1, S^q = +205 J mol^–1 K^–1

calculate the standard free energy change, D_rG^q, for the reaction:
PbO(s) + ½ O₂(g) ® PbO₂(s)

Select one:

a. +1.45 kJ mol^–1

b. –29.1 kJ mol^–1

c. –68.3 kJ mol^–1

d. –90.3 kJ m

1. draw a mechanism for the conversion of methoxybenzyl alcohol to methoxybenzaldehyde.

2.The ethyl acetate layer was extracted with 0.2M NaOH to remove traces of methoxybenzoic acid that result from additional oxidation of the aldehyde to the carboxylic acid. Explain how crystals of methoxybenzoic acid could be isolated from the NaOH solution.

3. Explain how TLC could be used to monitor the reduction of methoxybenzaldehyde to methoxybenzyl alcohol using NaBH4 as a reducing agent.

A student reacts 58g of salicylic acid with 10 mL of acetic anhydride producing 3.3g of acetyl salicylic acid. What is the percent yield of the reaction?

A galvanic cell consists of a iron electrode in 1 M Fe(NO3)2 and a copper electrode in 1 M Cu(NO3)2. What is the equilibrium constant for this reaction at 25oC? Enter you answer with 2 significant digits, using the syntax of "1.0x10(22)" for "1.0x1022"

  use the steady state approximation

2N2O5 (g) → 4NO2 (g) + O2 (g)

The mechanism is based on:

  N2O5 → NO2 + NO3    ka

  NO2 + NO3 → N2O5    k'a

  NO2 + NO3 → NO2 + O2 +NO   kb

  NO + N2O5 → NO2 + NO2 + NO2   kc