1 / 27

Water Solutions & Colligative Properties

Water Solutions & Colligative Properties. Definitions: solutions. A solution is a HOMOGENEOUS mixture of 2 or more substances mixed evenly at molecular level.. One part is regarded as the SOLUTE and the others as SOLVENT. Parts of a Solution.

edmund
Download Presentation

Water Solutions & Colligative Properties

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Water Solutions& Colligative Properties

  2. Definitions:solutions A solution is a HOMOGENEOUSmixture of 2 or more substances mixed evenly at molecular level.. One part is regarded as the SOLUTEand the others as SOLVENT

  3. Parts of a Solution • SOLUTE –material being dissolved (usually the lesser amount) • SOLVENT– material doing the dissolving (usually the greater amount) • Solute + Solvent = Solution

  4. moles solute ( M ) = Molarity liters of solution Concentration of Solute The amount of solute in a solution is given by its concentration.

  5. 1.0 L of water was used to make 1.0 L of solution. Notice the water left over.

  6. moles solute m of solution = kilograms solvent Another Concentration Unit: Add MOLALITY, m

  7. Concentration Units x 100% mass of solute x 100% = mass of solution mass of solute mass of solute + mass of solvent % mass (Percent by Mass) The concentration of a solution is the amount of solute present in a given quantity of solvent or solution. % by mass =

  8. II. Types of Solutions Ionic Solutes Molecular Solutes Definition:Solubility measures the maximum amount of solute that can be dissolved in a solvent at a given temperature (measures maximum concentration)

  9. K+(aq) + MnO4-(aq) IONIC Solutes 1. Most are HIGHLY soluble EX.KMnO4 = a handful can be dissolved in a teaspoon of water. aqueous solutions. KMnO4 in water

  10. 2.Dissolves in Water as Ions can conduct electricity Water solvent molecules attach to the ions (H end to the Cl-, O end to the Na+) Water solvent holds the ions apart and keeps the ions from coming back together

  11. Hydration of IONS Na+1Cl-1H2O Na+1 Cl-1 H2O shape = + - The polar ends of water surround the charged ions in the solid, neutralizing the charges allowing ions to move freely.

  12. Fig 10-34 Olmsted Williams • Interaction that helps a solid ionic crystal dissolve in water. • The arrows indicate ion-dipole interactions.

  13. B. MolecularSolutes (covalent compounds) • Most are INSOLUBLE (not soluble/ can’t bedissolved) • They do not have + or – for water to surround

  14. B. MolecularSolutes(covalent compounds) 2. SOME are very soluble. a. Polar molecules with OH bonds. (alcohols & sugars b. Acids (Have “H” in front) water grabs “H” forming hydronium acid HOH + HCl  HOH + Cl-1 H+1 Examples include: sugar ethanol ethylene glycol

  15. moles of solute liters of solution moles of solute m = mass of solvent (kg) M = C. Concentration of solutions (Molarity and Molality) Molarity(M) Molality(m) 12.3

  16. Molarity (M) = • Molality (m) = • Molarity is a temperature-dependent scale because volume (and density) change with temperature. • Molality is a temperature-independent scale because the mass of a kilogram does not vary with temperature.

  17. Molarity (M) = moles of solute Liters of solution M = mole A L solution EX:1. 75.0 grams of calcium chloride are dissolved in enough water to make 750. mL of solution. What is the molarity of this solution? *Remember* 1L = 1000mL = 0.901 M

  18. Molality (m) = moles solute kg solvent m = mole A kg B *Remember* 1g = 1mL for H2O 1000g = 1 kg Ex: What is the molality of a solution if 4.8gNaCl is dissolved in 500 ml of H20? = 0.164 m

  19. Molarity & Dilution of Solution • M1V1 = M2V2 • MConVCon = MdiluteVdilute

  20. Electrolyte Particles (i = ?) 1. Identification of “swimmers” in an aqueous solution • IMPORTANT – the colligative properties of freezing point and boiling point are proportional to the number of particles present in the solution. • particles, i • CaCl2 Ca+2 (aq) + 2 Cl –1 (aq) Ionic :i = 3 • CH3OH4 CH3OH4 (aq) Covalent: i=1 • H2SO4 2 H+1 + SO4 -2 Acids: i = 3 • Al2(SO4)3i = 5

  21. Review Colligative Properties A property that depends on the concentration of solute particles but not the identity of the solute Vapor Pressure Reduction Boiling Point Elevation Freezing Point Depression

  22. Freezing of a solvent Solvent Particles start to freeze Frozen Solvent

  23. Structure of Ice

  24. Freezing of a Solution Water with solute added Particles begin to freeze Solid formed

  25. Freezing Points

More Related