I eliminated the assignment for March 23rd in an attempt to shorten the unit

Answers found below

Solutions:

question 1

(a) PbCl2

it has the biggest value for Ksp. The fact that it is a 3rd order Ksp would actually increase the amount that dissolves.

question 2

Ksp = [Ca2+][OH-]**2 one point (two stars is old computer code for power)

[OH-] = 2x.022M = .044M another point

Ksp = 4.3 x 10**-5 point

four points total

question 1

(a) PbCl2

it has the biggest value for Ksp. The fact that it is a 3rd order Ksp would actually increase the amount that dissolves.

question 2

Ksp = [Ca2+][OH-]**2 one point (two stars is old computer code for power)

[OH-] = 2x.022M = .044M another point

Ksp = 4.3 x 10**-5 point

four points total

homework solutions

solutions below

2 points

question 1

(c) only PbSO4 will ppt.

plug in the given molarities for both Ksp formulae. You see that the Q value for Ag2SO4 is less than Ksp, but for PbSP4 is more than Ksp. Only PbSO4 will precipitate

question 2

addition of HCl increases solubility

HCl absorbs (neutralizes) OH- ions, causing a right shift, increasing dissolved Ca(OH)2

question 1

(c) only PbSO4 will ppt.

plug in the given molarities for both Ksp formulae. You see that the Q value for Ag2SO4 is less than Ksp, but for PbSP4 is more than Ksp. Only PbSO4 will precipitate

question 2

addition of HCl increases solubility

HCl absorbs (neutralizes) OH- ions, causing a right shift, increasing dissolved Ca(OH)2

If you can fire off an e-mail to let me know how you did on the quizzes, and what you had problems with, I would appreciate it.

We will use Gibb's Free Energy Equation to exploit the relationship between Randomness, Heat, and Free Energy (another way to express thermodynamic favorability).

Review and understand notes up to and including Gibb's Free Energy Equation

Positive Entropy Change (more disorder) is favored at high temperature (like evaporation)

Negative Entropy Change (less disorder) is favored at lower temperatures (like freezing)

The AP will not be testing on chapters 17 or 18

See your e-mail for details on review assignments