If a buffer solution is 0.160 M in a weak acid (Ka = 1.0 × 10-5) and 0.470 M in its conjugate base, what is the pH?

State the Born-Oppenheimer approximation and describe how its use simplifies the description of Hamiltonian operator for quantum chemical calculations. [4 Marks]

By describing the underlying principles of Hartree-Fock theory and density functional theory, briefly compare and contrast the two methods.

Is there any other way we could obtain the concentration of the protein fractions other than using Bradford assay?

(Hint: Fluorescent proteins)

1.) Determine the initial concentration of a solution of the weak acid HClO2 , if it its pH is 1.20 and Ka = 1.10

Sulfurous acid (H₂SO₃) has K_a1 = 1.500 × 10^-2 and K_a2 = 1.000 × 10^-7. Consider the titration of 60.0 mL of 1 M sulfurous acid by 1 M NaOH and answer the following questions.

What is the maximum number of protons that can sulfurous acid ionize (per molecule)?

b) Calculate the pH after the following total volumes of NaOH have been added. (Correct to 2 decimal places.)   No marks will be given if the number of decimal places is wrong.

i. 0.0 mL of NaOH  

ii. 30.0 mL of NaOH  

iii. 60.0 mL of NaOH  

iv. 90.0 mL of NaOH

v. 120.0 mL of NaOH

vi. 130.0 mL of NaOH

The reaction of methane with water to form carbon dioxide and hydrogen is
non-spontaneous at 298 K. Use the thermodynamic data from the table (it refers to 298 K) and determine at which temperature the system will make the transition from non-spontaneous to spontaneou

Substance:   CH4(g)    H2O(g)   CO2(g) H2(g)

ΔH° f (kJ/mol):   -74.87   -241.8    -393.5 0

ΔG° f (kJ/mol):   -50.81 -228.6 -394.4 0

S°(J/K·mol):   186.1     188.8   213.7 130.7

1) From the balanced molecular equations, write the complete ionic and net ionic equations for the following. (Use the lowest possible whole number coefficients. Include states-of-matter under the given conditions in your answer.)

a) SnCO₃(s) + H₂SO₄(aq) → SnSO₄(s) + CO₂(g) + H₂O(l)

b) Sr(NO₃)₂(aq) + H₂SO₄(aq) → SrSO₄(s) + 2 HNO₃(aq)

c) K₂C₂O₄(aq) + Pb(OH)₂(aq) → 2 KOH(aq) + PbC₂O₄(s)

2) Indicate what type, or types, of reaction each of the following represents. (Select all that apply.)

(a) 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g)

acid-base, combustion, double displacement, neutralization, oxidation-reduction, precipitation, single-displacement

(b) Sn(NO₃)₂(aq) + H₂SO₄(aq) → SnSO₄(s) + 2 HNO₃(aq)

acid-base, combustion, double displacement, neutralization, oxidation-reduction, precipitation, single-displacement

(c) C₄H₈O₂(l) + 5 O₂(g) → 4 CO₂(g) + 4 H₂O(g)

acid-base, combustion, double displacement, neutralization, oxidation-reduction, precipitation, single-displacement

(d) Al(OH)₃(aq) + 3 HBr(aq) → AlBr₃(aq) + 3 H₂O(l)

acid-base, combustion, double displacement, neutralization, oxidation-reduction, precipitation, single-displacement

1. in what context do the terms hydrophobic and hydrophilic relate to the soulubilites of substance in water?
2. in each of the following pairs of compounds which compound is likely to be more souble in CC14?
(a) Br2 or NaBr
(b) CH3CH2OH or CH3OCH3
(c) Cs2 or KOH
(d) I2 or CaF2
3. which sulfur conpound would you predict to be more souble in nonpolar solvents: SO2 or CS2?
4. methanol has a larger molar mass than water, but boils at a lower temperature. Suggest a reason why?
5. How is it that the dipole moment of HCI(1.08D) is larger than the dipole moment of HBR (0.82D) yet HBR boils at a high temperature?
6. why is methanol miscible with water but methane is not?

In the qualitative analysis scheme, magnesium and nickel precipitate from solution upon the addition of sodium hydroxide. Once separated from the remaining cations by filtration or decanting, the solid mixture is acidified and warmed to dissolve magnesium and nickel cations back into solution. Adding ammonia creates a buffer solution. (Remember, HCl and NH₃ makes for NH₄⁺ cation.) The buffered solution should just be basic (say, pH = 8). Adding sodium hydrogen phosphate (Na₂HPO₄) precipitates magnesium as MgNH₄PO₄ (Ksp = 3 x 10^-13).

a)Write the dissociation equation and corresponding Ksp expression

b)Calculate the molar solubility of the compound

Part 1) Solvent trapping is used for

a) analysis of trace components.

b) analysis of high-boiling major components.

c) analysis of low-boiling major components.

Part 2) Open tubular columns of less than 0.53 mm in diameter:

a) cannot be used for on-column injection of analyte with a standard injection needle.

b) do not give resolution as good as that of wider columns.

c) are excellent when used with thermal conductivity detectors.

Mechanism of Adsorption

Adsorption mechanism includes physical adsorption and chemical adsorption.

How well would the following compounds be adsorbed on (I) biochar and (II) clay?

1. Na⁺
2. NO₃^–
3. Dioctyl phthalate

Explain the answers in terms of physical adsorption and chemical adsorption.

A beaker with 125 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 mol L−1. A student adds 7.00 mLof a 0.360 mol L−1 HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.760. Express your answer numerically to two decimal places. Use a minus (−) sign if the pH has decreased.

Contrast ideal vs. nonideal/real gases, and explain why very high pressure and very low temperature gases behave nonideally. (6 points)