Equilibrium+Unit

Lesson Name: Introduction to Chemical Equilibrium
by Sykab Zihan

__**Summary**__
-A lot of chemical reactions are reversible. These reactions are always moving however there is a point where there is no net change in the amount of reactants and products. -At that point, the system is said to be at Equilibrium. Even though it's at equilibrium, the forward and reverse reactions do not stop. That is the reason the 2 process is said to be dynamic. -At equilibrium, the rates of the 2 processes are the same but the amounts of reactants and products are not always equal. -Equilibrium can only be reached when the reaction is in a closed system. -Equilibrium can be reached in both chemical and physical changes. For example: Chemical System is **2NH3(g)< -> 3H2(g) + N2 (g) ** Phase Equilibrium is **Br2(l) ****< -> ****Br2(g) ** Solubility Equilibrium is **MgCl2 ****< -> ****Mg2+ ****+ ****2Cl-(aq) ** -You can also represent a equilibrium graphically by constructing a concentration vs time graph. -You can find out where the equilibrium point by looking at where the slopes are 0. -To find the concentrations of the products and reactants, you must make a equilibrium constant. (Keq). -Keq is determined by comparing the concentrations of the products to the concentrations of the reactants at equilibrium in the equilibrium expression. -Keq is written as the concentration of the products raised to their molar coefficients divided by the concentration of reactants raised to their molar coefficients. -Some rules to determine Keq are: - The general form is aA (g) + bB (l) + cC (aq) > < dD (aq) + eE (s) + fF (g) -The Keq for the above formula would be (D) d (F) f / (A a )(C c ) __ **Homework** __
 * Solids and liquids are not included in the equilibrium. Only gases and aqueous solutions are included.
 * The molar coefficient must be raised as an exponent of the product or reactant
 * Pg 428 # 1-5**
 * Pg 430 # Do all**

By: Keshigaa Varatharasan -Wrote test for Equilibrium part A
 * Lesson Date:** November 28th, 2013
 * Lesson Name**: Equilibrium & Solubility

__Homework:__ Worksheet #1 : Solubility Problems Worksheet #2 : Solubility Equilibrium

è All equilibrium equations are dissolving equations Ex: Solid à breaking into its ions è Keq changes to Ksp, which stands for solubility products è Ksp indirectly represents the amount of solute that can be dissolved è Ksp represents maximum concentration of ions at equilibrium è Ex: Saturation Ex: molar solubility
 * //Review of Solubility & Equilibrium//**
 * What is Ksp? **
 * Ksp is an expression of mol/L
 * Soulubility is measured in g/100mL or g/L
 * The “x” value in a Ksp expression represents the solubility of salt in mol?L


 * Lesson Date: ** Friday, November 29, 2013
 * Lesson Name : ** N/A
 * By: ** Amandeep Pannu

No lesson. Ms.Wilson was absent.

**Work/Homework:** Complete chart at top of Solubility Equilibrium sheet. Read over sample problems and complete questions #1-10 from Solubility Problems sheet.


 * Links:**

[|Explanation of Solubility Equilibrium]
 * Video: **


 * Lesson Date:** Friday, Decemeber 6, 2013
 * Lesson Name:** N/A
 * By**: Amandeep Pannu

Today we worked on our in class write up for the //'Experimental Determination of the Ksp of Ca(OH)2'// Lab.

pg 549-all pg 550 #7,9 pg 560 # 21,22,32,40,66,68,69 pg 565 #18,21,24,25 pg 571 #36,37,39,42,43
 * Homework**: Study for the Solubility Equilibrium Quest on Monday. Complete all the worksheets and for extra practice do the following questions:


 * Lesson Date:** Monday, December 9, 2013
 * Lesson Name:** N/A
 * By:** Amandeep Pannu

No lesson was taught as we had our Solubility Equilibrium Quest today. The answers will be posted once we get them back.


 * Lesson Date:** Thursday, December 12, 2013
 * Lesson Name:** Equivalence Point
 * By:** Shuayb Rasool

In today's class we took up the Acid-Base titration virtual lab at : www.sciencegeek.net

Equivalence Point - equal moles of acid and base have reacted. End Point - where the indicator changes colour to.
 * Terms to know:**
 * Indicator - chemical that changes colour in response to pH changes.


 * Indicators are weak acids; the colour change is because of the loss or gain of protons

Kw = 1.0 * 10 [to the power of] -14 Kw = Ka + Kb

The __analyte is 0.1M HC2H3O2__ and the __titrant is 0.1M NaOH__
 * Example of the lab titration:**

The reaction is HC2H3O2 + NaOH ---> NaC2H3O2 + H2O (Weak Acid) + (Strong Base) ---> (Conjugate Base) + (Conjugate Acid) Therefore the equivalence point is at the following equilibrium: C2H3O2- + H2O <---> HC2H3O2 + OH- The C2H3O2- comes from acetic acid (a weak acid) and as such, becomes a weak conjugate base. The Sodium ion from the original equation comes from a strong base which means it has no affect on the overall pH. Therefore, C2H3O2- makes the solution have a basic pH.

Don't forget to consult your 3 graphs from this assignment for further understanding of the concepts of equivalence points!
 * It is important to note, the stronger the weak acid, the weaker the conjugate base and vice versa!


 * Lesson Date: ** Monday, December 16, 2013
 * Lesson Name:** Acid Base Equilibrium - Buffers
 * By:** Kayshani Kanagarajah

In today's class we had a lesson on buffers, and also learned how solve buffer questions. The notes include:

=__BUFFERS__=

-Buffers are mixtures of conjugate acid-base pairs that allow a solution to resisit change in pH. -Buffers have common ions in tehm that act as a reservoir and help maintain a relatively constant pH -Buffer probelms should be treated as common ion problems.

Examples of Buffers include: a) Acetic acid and sodium acetate b) Formic acid and sodium formate c) Ammonia and ammonium chloride d) Methylamine and methylammonium nitrate.


 * Sample Problem: **

A buffer is made by mixing 0.60 mol of acetic acid and 0.50 mol of sodium acetate on 2.0 L of water. Calculate: a) the pH of the orginal buffer b) the pH after the addition of 0.10 mol of OH - ignoring any volume change. c) the pH after the addition of 0.10 mol of H 3 O + ignoring any volume change.

*Note: Part b) and c) are to be solved as two seperate cases

Full solutions are shown below (Numbers on side are used to indicate steps)






 * Homework:** To complete all questions on the Acid and Base Equlibrium worksheet, and to do any acid base questions in the textbook under chapter 8. There will be an ISP on Tuesday, December 17, 2013 and Wednesday, December 18, 2013. Take this time to complete the questions and to ask question on Thursday or after the break. The quest will be on the week back from the holidays. Have fun practicing! :)

By: Keshigaa Varatharasan
 * Date:** December 17th, 2013
 * Lesson date:** NA

No lesson. Ms.Wilson was absent and we had an ISP - Complete Acid Bade Equilibrium Problems -for more practice complete questions from the textbook under chapter 8
 * Homework:** complete all questions from worksheet :

Review your work and be prepared to ask Ms.Wilson for help on an difficult questions or concepts.


 * Lesson Date :** December 18th, 2013
 * Lesson Name:** N/A
 * By:** Shuayb Rasool

There was no lesson today as we had a ISP due to the biology trip to //Ripley's new Aquarium//. A trip that, in fact, chemistry students did not get to participate in and share in the experience. It is important to also note that chemistry students were neither treated to a replacement trip or an apology, at the very least.


 * Homework:** complete the Acid-Base Problems worksheet and complete questions from chapter 8 in your textbooks


 * Lesson Date :** December 19th, 2013
 * Lesson Name: ** N/A
 * By: ** Shuayb Rasool

Today was only a 35 minute period and the day before the Winter break; suffice to say, we did nothing. But to go on record, we did **NOT** break any school rules that disallow eating in or around chemistry classrooms and the class was treated to a lovely, live performance by Randy.

- prepare for the Acid-Base Equilibrium test when we return after the break.
 * Homework:** complete the Acid-Base Problems worksheet and complete questions from chapter 8 in your textbooks

HAVE A GREAT HOLIDAY!