3. a) Calculate the pH of a sodium acetate-acetic acid buffer solution (Ka= 1.78 x 10-5) in
which the concentration of both components is 1.0 M. What would be the pH of the
solution if 1.5 mL of 0.50 M NaOH was added to 35.0 mL of the buffer? How much
does the pH change?

b) If the same amount and concentration of NaOH was added to 35.0 mL of pure water
(initial pH = 7), what would be the resulting pH change?

When calculating multicomponent distillation, why is it best to list the components in order of decreasing volatility?

How much energy per mole is required to transfer acetic acid, a byproduct of ethanol metabolism from blood to urine. The relevant concentrations are 33.00 and 674.00 ppm respectively and you are running a fever at 39^oC. State your answer in kJ/mol.

100 mL of a solution of compound “X” has the following properties:

–Molarity: 2M –MW of “X”: 500g/mole

–Density of compound “X”: 5.0g/cm3

What dilution factor would be required to make a solution of 1% (v/v) of “X”?

1. What is the role of the Dean-Stark apparatus and why is it filled with Toluene up to the top of the apparatus?
2. Should we observe any difference in the reaction rate between teams using the Dean-Stark apparatus and those not using it? Explain your answer.
3. Write a complete table of molar ratio for Acetophenone that is transferred into a metal functional group

A solution is 0.010 M in each of Pb(NO3)2, Mn(NO3)2, and Zn(NO3)2. Solid NaOH is added until the pH of the solution is 8.50. Which of the following is true?

Pb(OH)2, Ksp= 1.4 x10^-20

Mn(OH)2, Ksp= 2.0 x 10^-13

Zn(OH)2, Ksp= 2.1 x10^-16

A) No precipitate will form.

B) Only Pb(OH)2 will precipitate.

C) Only Mn(OH)2 wil precipitate.

D) Only Zn(OH)2 and Pb(OH)2 will preipitate.

E) All three hydroxide will preipitate.

a)

What is the value of ∆H of the following chemical reaction?

NaOH_(aq)        +       HCl_(aq) -----> NaCl_(aq)    +             H₂O_(l)      +                55.216 kJ

b) Use the above equation to calculate the amount (in moles) of the water produced if you know that the mass of the solution was 100 g, the temperature change was 3^oC, and the specific heat of the solution is 4.184 J/^oC.g.

c) 54.6 kJ of heat is released when 1 mole of HCl reacts with 1 mole of NaOH to produce 1 mole of NaCl and 1 mole of H₂O. Write a thermochemical equation for this reaction.

Indicate how the pKa of the ionizable group of histidine would be changed in a nonpolar pocket (increase/decrease) PLEASE EXPLAIN WHY. I thought it would increase but that's not correct

Sublimation is an example of a zero-order reaction. Provide other examples, and explain why the reactant available for reactions is unaffected by changes in the overall quantity of the reactants.

a.       Discuss which technique, simple distillation or fractional distillation, shall be the most efficient on purifying the mixture of solvents? Elaborate     (4 points)

b.      Which solvent should be distillated first, cyclohexane or Toluene? Elaborate.(3 point)

c.      How the RI measurements support (or not?) your expectations in the item b? (2.5 points)

d.      Making use of the RI measurements, explain if your distillation was successful. (3 points)

RI values:

e.       Would re-distillation of individual fractions improve the purification of individual solvents? Elaborate.                                                        (2.5 points)

A bomb calorimeter is filled with 9 atm of an unknown gaseous hydrocarbon fuel and an excess of oxygen gas at a temperature of 20.5 °C. The bomb calorimeter has a volume of 4.1 L and a heat capacity of 7.64 kJ/K. After the combustion reaction is complete the final temperature of the calorimeter is found to be 333.3 °C. Answer the following questions based on this information.

(a) What amount of heat in kJ was released from the combustion reaction of the unknown fuel? Please give your answer to 2 decimal places.

(b) What is the molar heat of combustion for the reaction in kJ/mol? Please give your answer to 2 decimal places.

(c) Given the table of data below, what is the identity of the unknown gas?

(d) What is the heat of combustion for the reaction in kJ/g? Please give your answer to 2 decimal places.

The following information is to be used for the next two questions. Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are εCo = 36400 and εNi = 5520 at 510 nm and εCo = 1240 and ε Ni = 17500 at 656 nm. A 0.556-g sample was dissolved and diluted to 150.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3-quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 0.866 at 510 nm and 0.218 at 656 nm in a 1.00-cm cell.

a.) Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample.

b.) Calculate the concentration of nickel (in ppm) in the initial solution prepared by dissolving the sample.

You have 0.4mL of acetic acid and 0.4mL of isoamyl alcohol for the experiment. Which is the limiting reactant?

A) What is the H_rxn^o in (kJ) for the reaction below, given the relevant table on the info sheet. PbO(s) + 2HBr(g) ---> PbBr₂(s)+H₂O(g).

a) -273

b) -229

c) -265

d) Not enough information provided.

B. What is the H_rxn^o in (kJ) for 2PbBr₂(s) + 2H₂O(g) ---> 2PbO(s) +4HBr(g) using the thermochemical equation in part A.

a) 545

b) 530

c) 458

d) 229