Chapter 14

Chapter 14

UNIT 12: SOLUTIONS DAY 1: Read the Article! Read the Article- Small, Yes, but Mighty: The Molecule Called Water Answer the Questions in your packet on Pages 3-4 Notes #1: Unique Role of Water

Importance of Water to Life Living cells are 70% - 95% water. The surface of the earth is approximately 70.9% water. Water is the only substance on earth that naturally occurs in all three states solid, liquid, and gas. Life is dependent upon water and its unique properties.

Notes #1: Unique Role of Water Importance of Water to Life Most of the reactions that take place in living organisms involve water, such as photosynthesis and cellular respiration. Background:

What is water? Water is a pure substance, a compound, of hydrogen and oxygen chemically bonded to form a single substance. Electrolysis breaks down water into hydrogen and oxygen. Notes #1: Unique Role of Water Physical

Properties: Boiling point: 100oC Melting point: 0oC Density: 1g/mL Specific heat: 1cal/g oC, which is also equal to 4.184 J/g oC Heat of vaporization: 540 cal/g What Makes Water so Special? Most liquids, when frozen, become

denser and sink. Solid water (ice) floats. Something to think about: What impact do you think that has on sea life? What do you think would happen to aquatic organisms if ice didnt float? Why does ice float? What Makes Water so Special?

Water molecules are polar. The water molecule has a bent shape giving it partial charges on its ends. The hydrogen atom is less electronegative than the oxygen atom so it loses the electron tug of war and becomes partially positive, and the oxygen pulls the shared electron closer to it, becoming partially negative. + +

What Makes Water so Special? Hydrogen bonding: Definition: an attractive force between a hydrogen atom of one molecule and an electronegative atom (such as nitrogen, oxygen or fluorine) of a second molecule. The hydrogen bonding of water gives it

some unique properties: 1. High Surface Tension: Caused by uneven attraction between water and air (water molecules will clump together) The hydrogen bonding of water gives it some unique properties: 2. High Specific Heat: absorbs a lot of heat. Requires a lot of energy to break bond. 3. Low Vapor Pressure: pressure of vapor above a liquid, caused by

escape of surface molecules 4. Heat of Vaporization: Amount of energy needed to convert liquid to gas 5. High boiling point: Takes more heat to disrupt the attractions between water molecules Water: The Universal Solvent Solution = A homogeneous mixture of two or more substances.

Solvent = Dissolving agent of a solution Whats doing the dissolving! Solute = Substance dissolved in a solution. Whats being dissolved! Aqueous Solution = A solution in which water is the solvent Rule: Like Dissolves Like Water dissolves ionic compounds Example: salt Water dissolves polar covalent

compounds Example: sugar Water does not dissolve nonpolar compounds Example: oil Water: The Universal Solvent Solution = A homogeneous mixture of two or more substances. Solvent = Dissolving agent of a

solution Whats doing the dissolving! Solute = Substance dissolved in a solution. Whats being dissolved! Aqueous Solution = A solution in which water is the solvent Like Dissolves Like Most ionic compounds will dissolve in water to form an aqueous solution, but when examining covalent molecules, only polar molecules those with partial charges will dissolve in water. This goes back to our rule, like dissolves

like: Water is polar, and as a polar substance, it will dissolve polar molecules and ionic compounds. Polar or Nonpolar? It boils down to symmetry. If the molecule looks like a copy of itself from top to bottom and left to right, then its going to be nonpolar.

HH vs. DAY 1: NOTES #1: Solutions Booklet pages 3-4 Homework: Page 5-6 Solutions Video http://www.youtube.com/watch?v=3G472AA

3SEs NOTES #1: Solutions What is a solution? A homogeneous mixture of two or more substances Solute? Substance dissolved in a solution

Solvent? The dissolving agent of a solution In the example pictured, identify the solute, solvent, and solution. Solubility

Definition: the Maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature and pressure. Remember, Like Dissolves Like! Nerdy Riddle of the Day: Why do white bears dissolve in water? Because theyre polar! Solubility

Soluble Substances are able to be dissolved Insoluble Substances are unable to be dissolved Types of Solutions

Aqueous Solutions: Homogeneous mixtures in which water is the solvent Aqueous Solutions Liquids can dissolve in other liquids to form solutions. Such liquids are defined as miscible. Example: alcohol and water If two liquids do not dissolve in one another, but rather separate upon standing, those liquids are defined as immiscible. Example: oil and water, or water and the lava in a lava lamp

Types of Solutions Electrolytes Compounds that conduct electricity. All ionic compounds form electrolytes when dissolved in water. Nonelectrolytes Do not conduct an electric current in aqueous solution or in molten form. Many molecular compounds

are nonelectrolytes Alloys Solids that dissolve in other solids Examples: brass, steel, etc Video Clip: Ionic vs. Covalent Solutions Click each compound to view:

Salt (ionic compound) - NaCl Sugar (covalent compound) - C12H22O11 Solutions vs. Things That Just Look Like Them Something to think about Is milk a solution? What about muddy water, dust particles floating or suspended in the air, or just the different gases

N2 , O2 , CO2 , H2O(g), Ar, etc. that make up the pure, unpolluted air we breathe? What makes a solutiona solution? Solutions are always transparent, meaning that light passes through with no scattering from tiny solute particles a solution may have a "color" but it will still be transparent. The solute component of a solution can be atoms, ions, or molecules, and will measure between 0.1 to 2 nm in diameter. Solutions are homogeneous and dont

settle out Solutions cannot be filtered, but can be separated using the process of distillation. Back to Basics: Mixtures Homogeneous Mixture: Mixture that has the same uniform appearance and composition throughout. May exist as gas, liquid or solid, depending on state of solvent.

Heterogeneous Mixture: Mixture that is not uniform in composition The 3 special types of heterogeneous mixtures that look like solutionsbut are NOT solutions!!!! 1. Suspensions: Heterogeneous mixtures with particles that have diameters

greater than 1000 nm. The particles of a suspension will separate upon standing. 2. Colloids: Heterogeneous mixture containing particles that are intermediate in size between those found in suspensions and true solutions that remain evenly distributed without settling out due to Brownian Motion Heterogeneous mixtures cont 3. Emulsions: Heterogeneous, colloidal

dispersions of liquid particles in a liquid medium. An Emulsion is a colloid- Shaving cream Difference between a solution, suspension, colloid, and emulsion: Suspensions will eventually separate; whereas colloids and solutions will not. Colloids can be distinguished from solutions using the Tyndall effect.

A beam of light passing through a true solution, such as pure unpolluted air/water, is not visible. Light passing through a colloidal dispersion, such as smoky or foggy air, will be reflected by the larger particles and the light beam will be visible. Solutions vs. Things That Just Look Like Them

Were BACK (to the top of page 8) Is milk a solution? What about muddy water? Dust particles floating or suspended in the air? The different gases that make up the pure, unpolluted air we NOTES #2: Solvation Booklet Pages 8-10 Homework: Page 11

To Dissolve or Not to Dissolve Solvation, also called dissolution, is the process of attraction of molecules of a solvent with molecules or ions of a solute. Forces between solute-solute molecules and solvent-solvent molecules must be broken before new solute-solvent attractive forces can form.

To Dissolve or Not to Dissolve Dissolution will occur if the solute-solvent forces of attraction are stronger than the attractive forces keeping the solute together and those forces keeping the solvent together. Dissolving will not occur if particles of a solute are more attracted to other solute particles than to the solvent. Same is true for solvent particles. Generally, if all three of the intermolecular forces of attraction are roughly equal, the substances will be soluble in each other.

Dissolution depends on the relative strength of three intermolecular attractive forces 1. Ion-Dipole Attractive Forces 2. Dipole-Dipole Attractive Forces 3. Induced Dipole-Induced Dipole Attractive Forces Ion-Dipole Attractive Forces This occurs between ionic compounds and a polar solvent (such as water)

A tug-of-war occurs for positive and negative ions between the other ions in an ionic crystal and the surrounding water (or other polar solvent) molecules. If the water pulls harder on the solute, the ionic compound will dissolve If the pull from the ionic crystal is stronger, the ionic compound will not dissolve. Dipole-Dipole Attractive Forces

Occurs between two polar molecules A polar molecule contains a bond in between ionic and covalent. Neither atom is strong enough to pull the electrons away from the other to form positive and negative ions like in ionic bonds. The electrons also aren't shared completely equally either as they are in a typical covalent bond.

Dipole-Dipole Attractive Forces Occurs between two polar molecules The bonds in these molecules are said to be polar, because they have partial positively and negatively charged ends, or poles, and are said to have a dipole movement. Hydrogen bonding is a particularly strong type of dipole-dipole force. Induced Dipole-Induced Dipole

Attractive Forces Also called London Dispersion forces Occur between nonpolar molecules and result from temporary charge imbalances. The temporary charges exist when the nucleus of one atom attracts electrons from the neighboring atom. At the same time, the electrons in one particle repel the electrons in the neighbor and create a short lived charge imbalance. Factors Affecting Rate of

Dissolution 1. Agitation or Stirring: Increases rate of dissolution, meaning the solute dissolves faster. 2. Particle size: Smaller particle size increases surfaces area and dissolves faster. Factors Affecting Rate of Dissolution 3. Temperature: Heating increases collisions between particles causing solute to dissolve faster.

4. Pressure (gases only): Increasing pressure increases collisions of gases, meaning that a gaseous solute will dissolve faster. Concentration This is one of the important properties of a solution. Concentration is a measure of solute dissolved in the solvent of a solution. Concentrated Solution containing a large

amount of solute dissolved in solvent Dilute Solution containing a little amount of solute dissolved in solvent. Concentration Example Example: Vinegar is a dilute acetic acid solution Vinegar is used in cooking or combined with oil in vinaigrette salad dressings. Concentrated acetic acid will kill you if ingested.

The only difference between such solutions is the concentration of the solute. Measures of Solute Concentration: Once you have identified the solute and solvent in a solution, you are ready to determine concentration. Concentration may be expressed several different ways.

1. Molarity number of moles of solute per liter of solution, abbreviated, M. Formula: M = mole solute / Liters solution Sample Problems 1. What is the molarity of a solution containing 0.50 mol glucose in 2.0 L solution? Molarity = Mols / Liter M = 0.50 mols / 2.0 L M = 0.25 M 2. What is the molarity of a solution containing 40.0 g NaCl in 700. mL of

solution? First change grams of solute to moles using molar mass: 40.0 g NaCl = 0.684 mol NaCl 40.0 g NaCl 1mol 58.443g NaCl Also change mL of solution to L (1 L = 1000 mL): 700. mL = 0.700 L Molarity = mols/Liter M = 0.684 mol / 0.700 L = .977 M

Homework is to complete page 11 NOTES #3: Solubility Curves Booklet Page 12 Homework Page 15 Solubility Curves Solubility: The amount of solute that dissolves per unit of solvent at a specific temperature and pressure to produce a saturated solution. Concentration of Solutions:

Saturated, Unsaturated, or Supersaturated? Saturated: A solution containing the maximum amount of solute per given amount of solvent at a constant temperature and pressure. Solubility Curves Unsaturated: A solution that contains less solute than a

saturated solution at a given temperature and pressure. Supersaturated: A solution that contains more solute than it can theoretically hold at a given temperature. Sing along.

http://www.youtube.com/watch?v=VTmfQU NLlMY Color coding your graphs will often help you read them more easily. See

example shown here. KNO3 1. How many grams of KNO3 can be dissolved in 100g of H2O at 50C? 80 g 2. If 70g of KNO3 is dissolved in 100g of water at 50C,

is the solution unsaturated, saturated, or supersaturated? Unsaturated (below the line) KNO3 3. If 105g of KNO3 is dissolved in 100g of water at 50C, is the solution unsaturated,

saturated, or supersaturated? Supersaturated (above the line) 4. Indicate whether the following are saturated, unsaturated, or supersaturated solutions: a. 30g of NaCl in 100g of H2O at 80C.

unsaturated b. 120g of KNO3 in 100g of H2O at 60C.supersaturated c. 92 g of NaNO3 in supersaturated 100g of H2O at 10C. Homework: Page 15 Sing alongone more time http://www.youtube.com/watch?

v=VTmfQUNLlMY DAY 5: 3/18/14 NOTES #4: Molarity & Concentration Booklet Page 16 Homework: Pages 16-17 Study Guide Pages 22-25 Day 4- Solvation Lab Pick up the lab and read it all once before

you begin. You will work in groups of ______. All work and calculations must be shown in order to get credit. You will have _____ minutes per station and then you will rotate clockwise. Completed lab is due tomorrow!

NOTES #4: Concentrations by Molarity Formula: M=n/V (in mol/L) Variables: M = molarity n = # of moles V = volume (in liters)

NOTES: Liters must be used as the unit for volume because molarity is measured in moles per liter, abbreviated, M. Conversion Factor: 1000 mL = 1 L (divide #mL by 1000)

Dont Forget!! Moles & Grams Conversions: Grams= #moles molar mass in g. 1 1 mole

Moles = # grams 1 mole 1 molar mass in g. 1. How many grams of sodium sulfate (Na2SO4)are required to prepare a 250 ml. solution whose concentration is 0.683M 250 ml 1 L = .250L 1 1000mL M = moles liters

.683M = n = .683 x .250 = 0.17075 mol .250L 0.17505mol 142.05 g Na = 22.99 x 2 = 45.98 1 1mol S = 32.07 x 1 = 32.07 O = 16.00 x 4 = +64.00 142.05g/mol

24.26g Na2SO4 = 24g Na2SO4 2. What is the molarity of an 85 ml. ethanol (C2H5OH) solution containing 1.77 g. of ethanol? 85mL 1L = .085L 1 1000mL 1.77g. 1 mol. = .0384 mol

C: 12.01 x 2 = 1 46.08g H: 1.01 x 6 = 6.06 O: 16.00 x 1= +16.00 46.08g/mol M

= moles = .0384 mol Liter .085L = .4517 = .45M C2H5OH 24.02 Homework: Pages

16-17 Independent Practice, Start Study Guide Pages 22-25 DAY 7: 3/19/14 NOTES #5: Dilutions Calculations Booklet Page 18 Homework: Page 18-19 Study Guide Pages 22-25 RECALL: Define the

following Dilute: Solution containing a little amount of solute dissolved in solvent. Concentrated: Solution containing a large amount of solute dissolved in solvent.

NOTES #7: Dilutions Formula: M1V1 = M2V2 Variables: M = molarity V = volume 1 = solution #1 match! 2 = solution #2

Units MUST NOTES Volume units MUST match so that they cancel when used in the above equation. Conversion Factor: 1000 mL = 1 L

Guided Practice 1. If a 12.5 M solution was diluted to 3 L that had a new molarity of .5 M solution, what volume of the original solution was added? M1 = 12.5 M V1 = ? M2 = 0.5 M V2 = 3 L (12.5 M)(V1) =(0.5 M)(3 L) (12.5 M)(V1) = 1.5 M*L 12.5 M 12.5 M

V1 = 0.12 L V1 = 0.1 L. 2. If 80 ml of an 8M solution was diluted into a 1 Liter container, what would the new molarity be? M1 = 8 M V1 = 80 mL M2 = ? V2 = 1000 mL (8 M)(80 mL) =(M2)(1000 mL)

640 M *mL = 1000 mL (M2)(1000 mL) 1000 mL M2 = .64 M M2 = 0.6 M. Homework: pages 18-19 Work on the Review on pages 22-25 (omit #4,5,7,& 9)

Recently Viewed Presentations

  • LTTC Celebration of New Thinking! Monday 1st February

    LTTC Celebration of New Thinking! Monday 1st February

    Rowena . Hennigan. The Design of E-Learning Resources for part time Distance Education Students. Teaching Fellowships: DIT 2. College . ... Theresa Ryan, Ziene Mottiar, Bernadette Quinn, Catherine Gorman, Kevin Griffin, Ruth Craggs and Deirdre Quinn .
  • Electromagnetic Waves - Mr. Slater's Science Class

    Electromagnetic Waves - Mr. Slater's Science Class

    Electromagnetic Waves All electromagnetic waves travel at the same speed through space (the speed of light) Gamma rays, X-rays, Ultra-violet waves, Light, Infra-red rays, Microwaves, and Radio waves are all electromagnetic waves with different wavelengths Some substances absorb EM waves,...
  • New Directions and Issues in Second Language Socialization ...

    New Directions and Issues in Second Language Socialization ...

    Study #2: Language Socialization in Multilingual, Multicultural Secondary School Classrooms in Canada (Duff, Mohan & Early, 1997; Duff, 2001, 2002a, 2002b, n.d.) Study #2 examined integration of Asian immigrant students in Western Canadian schools 50% of the school/district students are...
  • Resurrection: It changes Everything

    Resurrection: It changes Everything

    Typical response to opposition - fear. 16 And we have come to know and to believe the love that God has for us. God is love, and the one who remains in love remains in God, and God remains in...
  • Are You Smarter Than a 5th Grader?

    Are You Smarter Than a 5th Grader?

    Are You Smarter Than a 5th Grader? * * * * * * * * * * * * * * * * * * * * Are You Smarter Than a 5th Grader? 1,000,000 Test Taking Strategies Inference #1...
  • Keynote Talk: Innuagural Conference on Clickers

    Keynote Talk: Innuagural Conference on Clickers

    Clickers: A New Teaching Tool of Exceptional Promise Dr. Douglas Duncan University of Colorado, Boulder [email protected]
  • Statewide System of Support Foundational Services Illinois State

    Statewide System of Support Foundational Services Illinois State

    Kylene Beers makes an analogy we can all relate to in her book When Kids Can't Read, What Teachers Can Do. Here we have the "vocabulary casserole" which combines 20 unknown words, a typical dictionary, a weekly matching test and...
  • The Early Greeks - PC\|MAC

    The Early Greeks - PC\|MAC

    Define acropolis and agora. Name the requirements for citizenship in the Greek city-states. Sparta and Athens Chapter 4, Section 2, page 124 Chapter 4, Section 2 Objectives After this lesson, students will be able to: describe how tyrants seized control...