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Solutions Definitions Solution -Solution - homogeneous mixture Solvent Solvent - present in greater amount Solute Solute - substance being dissolved.

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Presentation on theme: "Solutions Definitions Solution -Solution - homogeneous mixture Solvent Solvent - present in greater amount Solute Solute - substance being dissolved."— Presentation transcript:

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2 Solutions

3 Definitions Solution -Solution - homogeneous mixture Solvent Solvent - present in greater amount Solute Solute - substance being dissolved

4 Solutions What the solute and the solvent are determines –whether a substance will dissolve. –how much will dissolve. A substance dissolves faster if it is stirred or shaken. –The particles are made smaller. –The temperature is increased. Why?

5 As size, rate As T o, rate 3. Agitation Factors Affecting the Rate of Dissolution 1. temperature 2. particle size 4. nature of solvent or solute More mixing, rate ∆ Surface Area

6 Solution = Solute + Solvent Solute - gets dissolved Solvent- does the dissolving –A–Aqueous (water) –T–Tincture (alcohol) –A–Amalgam (mercury) –O–Organic Polar Non-polar Dental filling Nightmare on White Street Chem Matters, December 1996

7 Classes of Solutions aqueous solution: water = “the universal solvent” solvent = water amalgam:solvent = Hg e.g., dental amalgam tincture:solvent = alcohol e.g., tincture of iodine (for cuts) organic solution:solvent contains carbon e.g., gasoline, benzene, toluene, hexane

8 Solution Definitions solution: alloy: solvent: the substance that dissolves the solute watersalt a homogeneous mixture -- evenly mixed at the particle level -- e.g., salt water a solid solution of metals -- e.g., bronze = Cu + Sn; brass = Cu + Zn “will dissolve in” refers to two gases or two liquids that form a solution; more specific than “soluble” -- e.g., food coloring and water miscible: soluble:

9 Types of Solutions SoluteSolventSolution Gaseous Solutions gas liquid gas air (nitrogen, oxygen, argon gases) humid air (water vapor in air) Liquid Solutions gas liquid solid liquid carbonated drinks (CO 2 in water) vinegar (CH 3 COOH in water) salt water (NaCl in water) Solid Solutions liquid solid dental amalgam (Hg in Ag) sterling silver (Cu in Ag) Charles H.Corwin, Introductory Chemistry 2005, page 369

10 Solid Brass An alloy is a homogeneous mixture of metals. Brass = Copper + Zinc Solid brass homogeneous mixture Copper Zinc

11 Brass Plated Brass = Copper + Zinc Brass plated heterogeneous mixture Only brass on outside Copper Zinc

12 Hardened Steel Iron Carbon Steel

13 Gold 24 karat gold 18 karat gold 14 karat gold Gold Copper Silver 18 / 24 atoms Au 24 / 24 atoms Au 14 / 24 atoms Au

14 Non-Solution Definitions insoluble:“will NOT dissolve in” e.g., sand and water immiscible:refers to two gases or two liquids that will NOT form a solution e.g., water and oil suspension:appears uniform while being stirred, but settles over time

15 Water HOT Solubility A B Before Water COLD Add 1 drop of red food coloring Miscible – “mixable” two gases or two liquids that mix evenly Experiment 1: Water HOT AFTER Water COLD A B

16 Solubility Water Oil T 30 sec AFTER Before Add oil to water and shake Immiscible – “does not mix” two liquids or two gases that DO NOT MIX Experiment 2: T 0 sec

17 Muddy Water: Dissolved Solids Muddy Water T 1 min T 5 min AFTER Water Before Add soil to water, shake well, and allow to settle Experiment 3: Dissolved solids can be calculated as a percentage: v/v (volume/volume) w/v(weight/volume) w/w(weight/weight) 5 mL solid / 95 mL water 5% v/v soil in water 5 mL / 100 mL = 5%

18 Muddy Water: Flocculation Muddy Water T 1 min T 15 min AFTER Water Before Add soil to water, shake well, and allow to settle Experiment 4: Muddy Water T 1 min T 5 min Water Before AFTER NO Flocculation material WITH Flocculation material Al 2 (SO 4 ) Ca(OH) 2  2 Al(OH) CaSO 4

19 Flocculation Mechanism Flocs by PAC stick to micro-sand by means of polymer. Items Removal Ratio (%) BOD 75 COD75 SS90

20 Centrifugation Spin sample very rapidly: denser materials go to bottom (outside) Separate blood into serum and plasma –Serum (clear) –Plasma (contains red blood cells ‘RBCs’) Check for anemia (lack of iron) Blood RBC’s Serum A AFTER Before B C

21 Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. Blood (a suspension) Centrifuge Blood plasma (a solution) White blood cells Red blood cells

22 Process of Dissolving

23 Making solutions In order to dissolve - the solvent molecules must come in contact with the solute. Stirring moves fresh solvent next to the solute. The solvent touches the surface of the solute. Smaller pieces increase the amount of surface of the solute.

24 O 2- H+H+ H+H+ H2OH2O  ++ ++ Water Molecule Water is a POLAR molecule

25 Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. Water molecules “stick” together to create surface tension to support light weight objects.

26 Water Molecule What is a polar molecule? How does the polarity of water effect this molecule? O H H Hydrogen bond  

27 Hydrogen bonds occur between two polar molecules, or between different polar regions of one large macro- molecule. One “relatively” negative region is attracted to a second “relatively” positive region. O H H H N H H Electronegative atoms Hydrogen bond

28 Interstitial Spaces Water dissolvedsolid Oil red food coloring Layer Non-polar Polar "immiscible" Water

29 Dissolving of solid NaCl

30 Polar water molecules interact with positive and negative ions Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 468 Animation

31 Na + Cl - NaCl solid salt NaCl (aq) = Na + = Cl - Dissolving of solid NaCl Animation by Raymond Chang All rights reserved.

32 Solvation  Solvation –  Solvation – the process of dissolving solute particles are separated and pulled into solution solute particles are surrounded by solvent particles

33 Dissolving of NaCl Timberlake, Chemistry 7 th Edition, page 287 HH O Na Cl hydrated ions

34 Dissolving of Salt in Water NaCl(s) + H 2 O  Na + (aq) + Cl - (aq) Cl - ions Na + ions Water molecules

35 Dissolving of Salt in Water NaCl(s) + H 2 O  Na + (aq) + Cl - (aq)

36 Particle Model of a Solution After mixing Saltwater solution Water molecule Chloride ion, Cl - Sodium ion, Na + Before mixing Fresh water Water molecule


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