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The dielectric constant of a solvent refers to its ability to diminish the attraction of solute for solute

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The dielectric constant of a solvent refers to its ability to diminish the attraction of solute for solute. In thermodynamic terms, solvents that have a high dielectric constant interact with solute with greater thermodynamic favorability than the solute does with other solute molecules. In the case of ions, this would involve the solvent interacting with cation and anion separately more favorably than cation interacting directly with anion. The potential energy describing the attraction of two ions can be written as:


, where e1 and e2 refer to the overall charge on each ion, D is the dielectric constant, and r is the distance between ions. Please use the following information provided below to calculate association energies for NaCl as a function of dielectric constant at constant distance, 0.01 nm.
Constant Parameters:
e1 = -1
e2 = 1
r = 0.01 nm
Dielectric Constant:
0.05
0.1
0.2
0.4
0.6
0.8
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7.5
8
8.5
9
9.5
10


Previous Questions I had to answer, I'm just going to include the answers if you need them for my question:
Based upon your calculations performed above, what trends can you identify? How does the potential energy describing cation:anion interaction depend on solvent dielectric constant?
See the graph below of dielectric constant vs potential energy. There is a direct relationship between the dielectric constant and the potential energy. The slope is negative, meaning that as you increase the dielectric constant, the potential energy decreases. This is consistent and correct since the lower the dielectric constant is, the weaker the interaction of the solvent and the ions.
??
Water and hexane have dielectric constants equal to 78.5 and 1.9, respectively. Consider a scenario wherein two ions of charge -4 and +4 are introduced into either solvent at a constant distance equal to 2 nm. Please calculate the association energies in water and hexane. What conclusion can you draw regarding solubility/insolubility of this ionic complex in water versus hexane?
Water:
PE = De1e2/r2
PE = (78.5)(-4)(4)/22
PE = -314


Hexane:
PE = De1e2/r2
PE = (1.9)(-4)(4)/22
PE = -7.6


Here's the question I need help on:
1A. Please calculate the pH of a 2 L solution containing 0.3 M acetic acid and 0.2 M acetate before and after the additional of 50 mL of 8 M KOH.
1B: Please address each of the following questions:

-Methylamine has a pKa = 10.5. Please calculate the ration of [A-] to [HA] at the following pH values: 2, 4, 6, 8, 10, 12, 14, and 16.
-Imidazole has a pKa = 6.9. Please calculate the ration of [A-] to [HA] at the following pH values: 2, 4, 6, 8, 10, 12, 14, and 16.
-Acetic acid has a pKa = 4.8. Please calculate the ration of [A-] to [HA] at the following pH values: 2, 4, 6, 8, 10, 12, 14, and 16.
-Please create plots of [A-]:[HA] ratio versus pH using the data generated in questions 1B(1-3) for methylamine, imidazole, and acetic acid. Please use these plots to identify the dominant ionization state at pH = 8.0 for each molecule