Introduction to Solutions and Solubility: Water- The universal solvent

DAY 63
December 5th, 2012
By: Ajaykumar Shanmugaraj
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Summary: Today's lesson was an introduction to the new unit: Solutions and Solubility
  • Solvents, Solutes and Solubility
  • Types of Solutions
  • Water- The universal solvent
  • Electrolytes
  • Miscible vs. Immiscible
Overview of Today's Lesson:
  • Students were introduced to a new topic which covers both solutions and solubility
  • Students were taught the components of a solution and the different types of solutions
  • Students were also taught that water is a universal solvent, and has unique properties
Solutions:
  • Solutions are composed of two things:
    • o Solvents: the substance that is larger in quantity and does the dissolvingimages (1).jpg
    • o Solutes: the substance that is smaller in quantity and is being dissolved
    • Concentrated solutions are those that are high in percentage of solute
    • Dilute solutions are those that are low in percentage of solute
    • Solubility: the maximum amount of solute that dissolves in a given quantity of solvent at a specific temperature. Measured in g/L, g/100L or mol/L
Types of Solutions:
  • Unsaturated Solution:
    • o A solution where more solute can be dissolved
    • Saturated Solution:
      • o A solution that has the maximum amount of solute dissolved in it. Therefore, no more of the solute can be added.
      • Supersaturated Solution:
        • o A solution that has more solute that its maximum capacity at a given temperature and specified volume of the solvent
        • Aqueous Solution:
          • o Any compound dissolved in water
Water:
  • Water is polar so only polar solutes and compounds can dissolve in it. This is known as "like dissolves like"
  • Polar molecules and ionic compounds are soluble in waterdownload (1).jpg
  • Non polar solutes are non-soluble in water because the solute-solvent attractions are weaker compared to the attractions between the solvent molecules. In other words, the intermolecular forces between the water molecules are too strong for the non-polar solutes to penetrate.
  • At times, water can cause molecular substances to ionize by Hydrogen bonding to H2O or London dispersion forces.
  • Electrolytes are ions that conduct electricity. Ionic compounds dissolve in water to produce electrolytes. Electrolytes are important because they carry messages from and to the brain and also maintain cellular function.
  • Salt is referred to as any ionic compound
  • Solids have a higher solubility at higher temperatures whereas gases have higher solubility at lower temperature. In other cases, halogens and oxygen are slightly soluble in water because they are very reactive.
Miscible Vs. Immiscible:

  • Miscible:download (2).jpg Are referred to as liquids that mix with each other
  • Water mixes well with polar molecules and ionic compounds






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  • Immiscible:
  • Are referred to as liquids that do not mix with each other
  • Non polar liquids do not dissolve in water
  • Any element that does not react with water is said to have a low solubility in water.




Useful References:
Websites:



Videos:
Textbook:
    • Section 8.2 (Page 376-380)
    • Section 8.3 (Page 382-389)
Homework:
      • Read page 376-379 and Page 382-387
      • Page 381 #1-3 and Page 389 #2,3,4,6



CONCENTRATION OF SOLUTIONS

By: Amentha Pusparajah

DAY- 66 (December.11.2012)


Summary: Today’s lesson was all based on Concentration of Solutions involving :

  • Molarity
  • Percent concentration
  • Concentration parts per million

Things you must know for this lesson:

    • Moles & Molar Mass
    • Conversions
    • Ratios

What happened in class:

  • Students handed in their assignment from yesterday
  • Students were taught how to calculate concentration by using the various equations portrayed below
  • Students were given time in class to complete H2 worksheet and ask questions if needed

Concentration = Amount of solute(mol) / Volume of solution(L)

C = n/V


  • The three ways of expressing concentration is by calculating:

    • Molartity (M)
      • M = Amount of solute(mol)/Volume of Solution(L)
    • Percent Concentration
      • % = (Amount of solute/Amount of solution) x 100
    • Concentration Part per Million
      • Cppm = (Mass of solute/Mass of Solution) x 106

  • There are three ways to calculate Percent Concentration:


    • Weight per weight
      • % w/w= (Mass of solute/Mass of solution) x 100

    • Weight per volume
      • % w/v= (Mass of Solute/Volume of Solution) x 100

    • Volume per volume
      • % v/v= (Volume of solute/Volume of solution) x 100

Homework:


Here are a few links to further assist you on this topic:


external image calculate-concentration-stock-diluent-800x800.jpg


Solubility Rules & Precipitation Reactions and Net Ionic Equations




By: Amentha Pusparajah
DAY- 67 (December.12.2012)

Today we had a new lesson on solubility that consisted of:

  • Solubility Rules
  • Precipitate Reactions
  • Net Ionic Equations

Things you must know for this lesson:

  • Forming Ions
  • Writing and balancing chemical equations

What happened in class:

    • Questions from yesterday’s homework was taken up
    • Students viewed a demonstration on chemical reaction results based of the three compounds: NH4Cl, KI, and Pb(NO3)2
    • Students were introduced to the solubility table on Pg 424 and were taught the general solubility rules
    • They learned how to determine the net ionic reactions
    • Students were given time in class to complete H2 worksheet in class

General Solubility Rules:

  • Salts (ionic compounds) are more soluble in hot water and gasses are more soluble in cold water note that there are some exceptions
  • Alkali Metals (Group 1) salts are very soluble in water
  • Ammonium (NH4) salts are very soluble in water
  • Salts containing the nitrate ion, NO3- and acetate ions, C2H3O2- are very soluble in water
  • Most salts containing Cl-, Br -, and I- are soluble in water except salts containing Ag+ and Pb+

Precipitation Reactions:

à refers to the formation of a solid from ions.
    • Precipitate is “insoluble” and the symbol is (s)
    • Precipitation indicates a chemical reaction occurred

Net Ionic Reactions:


The equations can be divided into 3 types:
1) Molecular
2) Ionic
3) Net Ionic

external image 129310629.png

In order to determine net ionic reactions is by:


STEP 1: Writing the formula for reactants and products using valences

Ex) NaOH + MgCl2 à NaCl + Mg(OH)2

STEP 2: Determine if any products are insoluble (use solubility rules). ** all reactants must me aqueous in order to mix. If all the products are aqueous: no reaction has occurred.

Ex) NaOH (aq) + MgCl2 (aq) à NaCl (aq) + Mg(OH)2(s)

STEP 3: Balance the equation.

There are to conditions for molecular, ionic and net ionic equations:
Materials balance: both sides should have the same number of each atom
Electrical balance- both sides of a reaction should have the same net charge
Ex) 2NaOH (aq) + MgCl2 (aq) à 2NaCl (aq) + Mg(OH)2(s)

STEP 4: Write the ionic equation.

Ex) 2Na+ + 2OH- + Mg+ + 2Cl- à2Na+ + 2Cl- + Mg(OH)2

STEP 5: The net equation.

After writing the ionic equation you will realise that there will be some irons that are common to both the reactant and product side of the equation therefore they do not impact the reaction
à These common ions are called Spectator Ions
These spectator ions are cancelled from each side of the equation, leaving the Net Ionic Equation!
Ex) 2Na+ + 2OH- + Mg+ + 2Cl- à2Na+ + 2Cl- + Mg(OH)2
Ex) 2OH- + Mg+ à Mg(OH)2

Homework :


Complete worksheet H2
Textbook Questions: Page 484 #1-9 ** Ms. Wilson is checking homework!

Here are a few links to further assist you:


http://pages.towson.edu/ladon/practicenieanswers.htm
http://www.occc.edu/kmbailey/chem1115tutorials/Net_Ionic_Eq
http://www.kentchemistry.com/links/Kinetics/netionic.htm
ns.htm




Day 74
January 7th, 2013
By: Rahman Shaikh

Summary: Today we reviewed Arhennius Theory and completed Bronsted-Lowry theory.
  • We learned about hydrogen donors and acceptor
  • Acids and bases come in pairs
  • Conjugate base and Conjugate Acid
  • Strengths of acids and bases

Bronsted Lowry Theory
  • Acid is a hydrogen ion donor(H+ or proton)
  • Base is a hydrogen ion acceptor

Acids and Bases come in pairs
  • A conjugate base is the remainder of the original acid, after it donates it's hydrogen ion
  • A conjugate acid is the particle formed when the original base gains a hydrogen ion
  • Examples of conjugate acid and base pairs
    • NH3(aq) + H2O (l) <--> NH4(aq) + OH(aq)
    • Base--------Acid-----------Conj.Acid---Conj.Base

    • HCl + H2O <--> H3O + Cl
    • Acid---Base------Conj.A--Conj. B
  • Therefore conjugate acid-base pair is related by the loss or gain of a single hydrogen ion
  • Amphoteric is a substance that can act as both an acid and base. For example,water.

Strengths of Acid and Bases
  • Strong acids ionize completely in water, which is 100%.Contains 2 or more oxygen per hydrogen. Ex. HCl, HBr, HI, H2SO4, HNO3
  • Weak acids ionize slightly in water (less than 50%). Ex. HF, HNO2, HC2H3O2. Organic acids are usually weak acids.
  • Strong Base dissociates completely in water (100%). Ex. All metal hydroxides with the exception of Be
  • Weak Base ionize slightly(less than 50%) in water. Ex. NH3 or any other base.

Homework
  1. Complete acid and base worksheet questions 1-3.
  2. Read pg.473-474.
  3. Bring a scientific calculator.




Day 75
January 8th, 2013
Rahman Shaikh

Summary: Today we learned and focused on the pH scale and how to calculate the pH of solutions.
  • Self ionization of water
  • ion product constant
  • the pH concept 0-14
  • calculating pOH
  • pH and significant figures

Self ionization of water
  • water ionizes and forms ions, this is called self ionization. H2O (l) + H2O (l) <--> H3O (aq) + OH (aq)
  • this occurs to a very small extent: [H3O] = [OH] = 1 X 10^-7

The pH concept, calculating pOH, pH scale
  • pH stands for hydrogen power
  • Measured with the numbers 0-14
  • In a neutral solution pH is 7
  • In an acidic solution pH is <7
  • In a basic solution pH is >7
  • equal amounts of hydronium and hydroxide means that a solution is neutral
  • more hydronium than hydroxide means that the solution is acidic
  • more hydroxide than hydronium means that the solution is basic
  • therefore the pH scale indicates the hydronium ion concentration
  • pH = -log [H3O]-----------(for acids)
  • pOH= -log [OH]------------(for bases)
  • pH + pOH = 14
  • [H3O] = 10^-pH
  • [OH] = 10^-pOH

pH and Significant Figures
  • the hydrogen ion concentration is usually expressed in scientific notation, in pH calculations
  • the amount of significant digits the Molarity has gives you the amount of decimal places the pH should contain; vice-versa.





Day 76
January 9th, 2013
Rahman Shaikh

Summary: Today's lesson was on Titration and Stoichiometry
  • Neutralization Reaction
  • Tiration
  • Stoichiometry and Calculations

Neutralization Reaction
  • a reaction in which an acid and a base react in an aqueous solution to produce a salt and water (H2SO4 + 2KOH --> K2SO4 + 2H2O)
  • in this reaction a proton is transferred from the strongest acid to the strongest base, according to Bronsted-Lowry theory

Titration
  • titration is the process of adding a known amount of solution of known concentration to determine the concentration of another solution
  • the equivalent point is when the moles of hydronium ions is equal to the moles of hydroxide ions
  • the end point is the point during a titration when a sudden change in colour of an acid-base indicator occurs
  • an indicator is used to show when neutralization has occurred
  • phynolphthalein is a common indiactor; it is colourless in neutral and acid, and turns pink in base
  • Steps for titration reaction
    1. A measured volume of acid of unknown concentration is added to a flask.
    2. Several drops of indicator is added.
    3. A base of unknown concentration is slowly added, until the indicator changes colour; measure the volume

Stoichiometry and Calculations
  • titration stoichiometry is similar to solutions stochiometry, therefore all the steps are similar
  • Steps
    1. Add the acid and base, and write out the rest of the equation and balance it.
    2. After step 1, use the chart learned earlier in the moles and stoichiometry unit. This time it will include molar ratio, concentration, volume, moles, molar mass, and mass. Some of these might not be needed for all questions.
    3. Use the chart to figure out the unknowns that are needed.

Homework
Do sample problem 2, and question 1-7 on the titration-neutralization reactions worksheet.


external image placeholder?w=849&h=50Day 77
Thursday, January 10, 2013
Fairuz Shahriar

  • Complete the Purpose and Materials (in 2 columns) of the Micro titration lab sheet.
  • Bring goggles for the lab tomorrow.
  • We received the Grade 11 Chemistry review sheet.
  • HW: 1. P. 491-496 - Chapter 10 Review, P. 500-508- unit review select questions

Exam reviews:

Micro Titration Lab sheet:
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Day 78
Friday, January 11, 2013
Fairuz Shahriar

  • The Micro Titration lab was performed today. Purpose of the lab was to find the unknown concentration and observe the process of titration and perform it ourselves. The materials are: 10 mL graduated cylinder, 0.1 M of HCl, Phenolphthalein, Dropper bottles, Goggles, 0.1 M of NaOH.
  • We had to do both the procedures 3 times, and worked in pairs.

Important dates:

v Chemistry test on Monday (January 14, 2013) on Unit 4.
v ISU due on Tuesday (January 15, 2013).
v The Micro titration lab is due Thursday (January 17, 2013). You need to hand in the lab sheet complete with all the answers and a good copy of the observation table. Make sure you all got your data tables signed!

Unit test review questions:

Notes:


GOOD LUCK FOR THE TEST!

Day 79
January 14, 2013
Fairuz Shahriar

We started working on a new unit: Gases and atmospheric chemistry

Ø Read pg. 516-519. Complete questions from pg. 519 #1-6.
Ø Make notes on Pg. 541-542


Atmospheric pressure is defined as the force per unit area exerted against a surface by the weight of the air molecules above that surface.


This should be helpful:



http://www.emsb.qc.ca/laurenhill/science/kinetic.html

http://www.hhs.homewood.k12.al.us/~kreaves/KineticMolecularTheory.html

http://www.sdbor.edu/educators/praxis/bhsu/documents/ms_sc3.pdf



PressureChart.png



















DAY 80
January 15, 2013
Rafi Yama

Overview of lession: In todays class we continued our lesson on gases and introduced to Boyle's Law.

Key points of lession:
  • The relationship between Pressure and Volume.
  • Boyle's Law
  • P1V1=P2V2

What happened in class:
  • Chemistry watertreatment ISU was handed in.
  • Students learned Boyles law on Volume and Pressure.
  • Students were taught how to calculate Pressure and Volume with the new equation discussed (P1V1=P2V2)
  • Homework assigned.

P1V1=P2V2:
  • P1 - Pressure 1 (kPa)
  • P2 - Pressure 2 (kPa)
  • V1 - Volume 1 (mL)
  • V2 - Volume 2 (mL)
  • *Remember when solving these questions to put in; P increses therefore Volume will decrease* YOU WILL BE DEDUCTED MARKS IF MISSING THIS STEP!!

Boyle's Law:
  • Boyle's Law states that at a constant temperature, as the volume of a fixed amount of gas increases, pressure decreases.
  • Therefore with Boyles law, mathematically we can use the equation P1V1=P2V2
  • Keep in mind that Volume and Pressure are inversely related.
BoylesLaw.jpg
Homework Assigned:
  • Text book reading was assigned: Pages 554-556, 520-521, 528-531
  • As a reminder the
  • Look over notes taken in class.

Other resources of information on Boyle's Law:



DAY 81
January 16, 2013
Rafi Yama

Over view of lesson: In today's cass we spent the class on a lab based on Charles' Law and the Properties of Gases

Key Points of Lesson:
  • Charles' Law
  • Relations of gas and water temperature

What happened in class:
  • Today we had a lab, and made a observation table to record quantitative results.
  • Assigned homework questions which are the lab questions.

Charles' Law:
  • Charles' Law (also known as the Law of volumes) is an experimental gas law which describes how gases tend to expand when heated.
  • This Law applys for Gases.

Summary of Today's Lab:
  • The lab we did today was with a syringe, we filled it up to 7mL of oxygen and tightly placed a cap to seal the gas in the 7mL of the syringe.
  • Next we filled a large beaker with ice water and tap water.
  • After we put in the syringe and a thermometer.
  • Soon after we started taking quantitative mesurements, we went back and forth pooring out some water and refilling the large beaker with slightly warmer water.
  • All measurements were recorded onto the observation tables students made beforehand.

CharlesLaw.jpg



This image shows, the same balloon in a) cold water and b) warm water.
This image shows how gas has expanded because of the warm water and shrunk in
the cold water.







Homework Assigned:
  • Homework questions assigned are on the back of the prodedure sheet given for today's lab.
  • MICROTITRATION LAB which is due tomorrow.

Other resources of information on Charles' Law:




DAY 82
January 17, 2013
Rafi Yama

Overview of lesson: Students were intoduced to Gay-Lussac's Law.

Key points of lesson:
  • Gay Lussac's Law
  • Gas relations between Pressure and Temperature

What happened in class:
  • Yesterday's lab questions were discussed.
  • Gas Law sample problems and homework assigned.

Gay-Lussac' Law:
  • This law applies to gases at a constant volume allowing pressure and temperature to change.

Gay-LussacsLaw.gif

P1/T1=P2/T2:
  • P1 = Pressure 1 (kPa)
  • P2 = Pressure 2 (kPa)
  • T1 = Temperature 1 (K)
  • T2 = Temperature 2 (K)
  • Remember when solving these types of problems to include; *as the Temperature increases, Pressure will increase*
Gay-LussacsLaw2.gif
Homework Assigned:
  • Complete Gas Laws Problems sheet given at the end of class today.
  • Homework questions are on; Charles Law, Boyles Law, Gay-Lussac's Law.

Other resources of information on Gay-Lussac's Law:




Hey there A Period Chemistry Classmates!

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No one informed you all (on the wiki) that there is an ISU DUE JANUARY 15

Read pages

429 - 438

442-443

Do

436 # 1-14

441 # 1-13

443 # 1-7

The questions you have to research need to be typed.

This was assigned on the 18 of December.

-I totally forgot to post this at the beginning of the break, sorry <3



Decided this needed some sprucing up + Humour (credit to the 12s)reaction.jpg

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