hi there guyss! On monday, we corrected the work sheet called "solubility equilibria assignment #3. And also, we looked at pages 36-37. We learned how to determine if a solution is saturated or unsaturated.

Remember guyyys!:
- Q-Ksp, the solution is just saturated and no ppt( no precipitation)
-Q> Kso, the solution is saturated and a ppt occurs.
- Q< Ksp, the solution is unsaturated and no ppt formed.

GOODLUCK ON THE TESST' DUN DUNN DUUUUUNNN......
the scribe for thursday will be arjel:)

May 07, Friday

I wasn't late today, so I volunteered to do the blog. :) :)


First, we did the questions 3 & 4 in the Solubility Equilibria Assignment #1. Obtain the answers from Ms. K. Note: in letters b and d you have to change the unit to moles/liter before you can solve for the Ksp.


We also went over the pages 31-35 on the Chemical Equilibrium booklet. In that, we learned a new lesson, determining ion concentration from Ksp. For all of you who hates ICE, you'll life will be easier. It's no different from the ICE method we've been doing, except that:

• the initial concentration of the ions (products), before dissolving, is zero.

• reaction is consists of a saturated solution as reactants and ions as products so you get to IGNORE the saturated solution, the solid one, in your ice table.

Example: The Ksp of magnesium hydroxide is 8.9 x 10 ⁻12. Determine the solubility of Mg(OH)₂.

• Mg(OH)₂(s) <=> Mg2+ (aq) + 2OH⁻(aq)

I...............___.................0................0
C.............___................+x................+2x
E..............___...............+x................+2x


To solve for x, use the formula, Ksp = [products] and substitute the values. We'll find that the solubility of Mg(OH)₂ is 1.3 x 10-4.


That's determining ion concentration using Ksp in PURE WATER. Another thing we learned is determining ion concentration with an ION IN COMMON WITH THE COMPOUND.

Example: The Ksp of magnesium hydroxide is 8.9 x 10 ⁻12. What is the solubility of magnesium hydroxide in a 0.10 M solution of NaOH.

Step 1: Determine the concentration of the common ion, OH ⁻.

NaOH(s) <=> Na+(aq) + OH -(aq)
[OH⁻] = [NaOH] = 0.10 M

Step 2: Set up an ICE table for Mg(OH )₂.

• Mg(OH)₂(s) <=> Mg2+ (aq) + 2OH⁻(aq)

I...............___.................0................0
C.............___................+x................+2x
E..............___...............+x................0.10 +2x

***You have to include the concentration of OH - from NaOH(s) in the table because when we dissolve Mg(OH)₂ in the solution, OH ions are present. According to Le Chatelier's Principle, adding more OH ions to a saturated solution would increase the overall concentration of the products shifting the equilibrium to the left. This would result in more solid formed and a decrease solubility.***


Step 3: Substitute values into the solubility product expression.

Ksp = [Mg2+][OH-]2

8.9 x 10⁻12= (x)(0.10 + 2x)2

**at this point, you can see that you'll have a quadratic equation if you solve further, so, ignore the x of the ion in common, OH. Ms. K said that it's too tiny to matter.**

8.9 x 10⁻12= (x)(0.10)2

8.9 x 10⁻12= 0.01x

8.9 x 10⁻10M = x

Let's check if the value makes sense. The solubility of Mg(OH)₂ in pure water is 1.3 x 10-4 M and in a 0.10 solution of NaOH is 8.9 x 10⁻10M. The solubility decreased, just as we predicted.



I dont know if I have to pick for someone to do the next scribe... if so, i'll pick Ericka! :) :)

Common Ion Examples

Common ion

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Ksp Examples from Notes

Ksp problems

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May 4 AND 5

SOOO pretty much what we did on May 4 is go over the study guide questions which Ms. Kozoriz already put up the answers to. We studied the rest of the period because test was on MAY 5th!

I really don't know what else to put... and I feel like I should scribe for May 6 since this post is quite short and sad.

Ch. 18 Chemical Equilbrium

Ch18equilibrium

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Thursday, April 22 and Friday April 23

On Thursday we went over and corrected the Equilibrium Project Assignment, pages 1 questions 1-4 and page 2 questions 5-11. After that we worked on Lesson 3 Homework Assignment and did questions 1-5.

We also were given a assignment that is to be handed in Determining Equilibrium.


On Friday we did our Equilibrium & Le Chatelier Analogy Lab which should be handed in today.


That wraps up what we did before the weekend.