Physical Chemistry

A)The electrolytic conductivity of 0.10 M solution of acetic acid
is 5.3x 10-5 Scm-1. The cell constant was 0.10 cm-1. Neglecting activity
coefficient, Calculate the acid dissociation constant (Ka).
(Λmo for acetic acid = 390. S cm2 mol-1)

B)The observed osmotic pressure of 0.1 M acetic acid solution is
2.45 atm at 25.0 oC. Calculate the Van’t Hoff factor (i) and the degree of
ionization (α). Compare your value with that obtained from problem 1.
Comment on your answer.

An unknown compound contains only C, H, and O. Combustion of 3.90 g of this compound produced 9.18 g of CO2 and 2.51 g of H2O.

What is the empirical formula of the unknown compound?

Calculate the vapor pressure of a solution containing 25.3 g of glycerin (C3H8O3) in 119 mL of water at 30.0 ∘C. The vapor pressure of pure water at this temperature is 31.8 torr. Assume that glycerin is not volatile and dissolves molecularly (i.e., it is not ionic) and use a density of 1.00 g/mL for the water.

The boiling point of water is 100.0°C at 1 atmosphere.

How many grams of iron(II) chloride (126.8 g/mol), must be dissolved in 217.0 grams of water to raise the boiling point by 0.450°C? Refer to the table for the necessary boiling or freezing point constant.

The following half-reactions combine to make an electrolytic cell:

K+ (aq) + e-  K (s) E0 = −2.93

Li+ (aq) + e-  Li (s) E0 = −3.05

If a current of 1.5 Amps is placed on this cell for 5 minutes, which of the following describes the mass of solid formed (in grams) and the voltage required of the current. [1 Amp = 1 coul/s; 96500 coul = 1 mol e-]

The next 7 questions are related to the titration of 60.0 mL of a 0.0250 M Zn2+ solution with 0.0600 M EDTA in a solution buffered at pH 9. Assume that the temperature is 25 oC and that the formation constant for Zn2+ is 3.13 x 1016 at this temperature. How many mmols of Zn2+ are present in the solution before the titration begins? What volume of the EDTA solution is needed to reach the equivalence point? What is the conditional formation constant for Zn at this pH? What is the pZn of the analyte solution before the titration begins? What is the pZn of the solution after 15 mL of titrant have been added? What is the pZn at the equivalence point of the titration? What is the pZn of the solution after 30 mL of titrant have been added?

Copper is added to steel in amounts greater than 0.2% but less than 1.5% as it strengthens, hardens and reduces corrosion of the product. The amount of copper in a steel product is determined by digesting the steel product with strong acid, converting all copper species to the Cu+1 ion, complexing the Cu+1 ion to form a light absorbing species by reaction with neocuproine, and extracting the coloured complex with isoamyl alcohol for analysis by UV/VIS spectrophotometry at the 454 nm absorbance wavelength. A 0.2108 g sample of a standard steel sample containing 0.42% of copper was analysed by the above process and a final 10.00 mL volume of the isoamyl extract was obtained. The copper complex of this solution gave an absorbance of 0.481 using a 1.00 cm cuvette. A 0.2892 g sample of a steel product that was being manufactured was analysed as above using the same procedure and equipment and a final 10.00 mL volume of the isoamyl extract was obtained. The copper complex of this solution gave an absorbance of 0.632 using a 1.00 cm cuvette. A blank solution carried through the same procedure gave an absorbance of 0.038. What is the percentage of copper in the manufactured steel product? Is the copper in this steel product within the specified range given above. Note. You have to take into consideration the absorbance of the blank solution to solve the problem.

A buffer was prepared by adding 0.1 mmoles of solid isoelectric histidine to 0.1
mmoles of solid histidine monohydrochloride and adjusting the final volume to
0.5 liters. The pKas for histidine are 1.8, 6.0, and 9.2. What is the pH of this
buffer?

At 1 atm, how much energy is required to heat 89.0 g of H2O(s) at –12.0 °C to H2O(g) at 173.0 °C?

1) All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements. Which law does this refer to?

2) Determine the number of protons, neutrons and electrons in (65-top) (29-bottom)X

3) What species is represented by the information: p+ = 47 n

N atoms have a high electronegativity. However, N atoms have no electron affinity, meaning that N atoms do not attract electrons. Explain how and why these facts are not inconsistent.

A solution of a theoretical triprotic acid was prepared by dissolving 4.251 g of solid in enough DI water to make 500.0 mL of solution. 13.65 mL of a 0.572 M solution was required to titrate 20.00 mL of this acid's solution.

What is the molar mass of the acid?

Consider the titration of 25.00 mL of 0.0750 M Sn²⁺ with 0.1000 M Fe³⁺ in 1 M HCl to give Fe²⁺ and Sn⁴⁺ , using a Pt electrode for the cathode and a Standard Hydrogen Electrode for the anode (connected to negative terminal of potentiometer).

e) Sketch the titration curve and indicate the equivalent pt, and the E_titr when ½ of the moles of analyte has been oxidized.

A 10.5L bulb contains NH₃ gas and HCl gas, which have equal partial pressures. The total gas pressure is 1.86atm and the temperature is 302K. These gases react completely:

            NH₃(g) + HCl(g) → NH₄Cl(s)

Calculate the mass of NH₄Cl formed.

*** Show your work

*** The answer is 21.1g but PLEASE show all of your work CLEARLY so I can understand! THANK YOU!!