1 / 17

Colligative Properties

Colligative Properties. How does the solute change the properties of the solvent?. Consider aqueous solutions Solvent = water How do properties of aq solution compare to properties of pure water?. Conductivity. Pure water does not conduct electricity Some solutions do

gamba
Télécharger la présentation

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. Colligative Properties

  2. How does the solute change the properties of the solvent? • Consider aqueous solutions • Solvent = water • How do properties of aq solution compare to properties of pure water?

  3. Conductivity • Pure water does not conduct electricity • Some solutions do • To conduct a current, solution must contain ions • Conductivity depends on nature of the particle • Molecular solutes do not conduct

  4. Colligative Properties • Depend on number of particles in solution not on type of particles • Doesn’t matter what kind of particles: can be ions or molecules • Concentration of particles doesmatter

  5. What are some colligative properties? • Vapor Pressure Lowering • Freezing Point Depression • Boiling Point Elevation • change in Osmotic Pressure • The higher the concentration of solute particles, the larger the effect

  6. Does it matter if solute is ionic or covalent? • number of particles will vary • Ionic solutes • dissolve to produce (+) & (-) ions more particles per mole of solute • Covalent solutes • 1-to-1relationship betweenmoles of solute and moles of dissolved particles

  7. C6H12O6 • Covalent • Dissolves as molecules: C6H12O6(s)+ H2O(l)  C6H12O6(aq) • 1 mole sugar → 1 mole molecules

  8. NaCl • Ionic • Dissolves as ions: NaCl(s) + H2O(l)  Na+1(aq) + Cl-1(aq) • 1 mole salt  2 moles ions

  9. MgCl2 • Ionic • Dissolves as ions: MgCl2(s) + H2O(l)  Mg2+(aq) + 2Cl-(aq) • 1 mole salt 3 moles ions

  10. As solute is added to a solvent, what happens to freezing point & boiling point of solution? • The freezing point ↓ & the boiling point ↓ • The freezing point ↓ & the boiling point ↑ • The freezing point ↑ & the boiling point ↓ • The freezing point ↑ & the boiling point ↑

  11. Which solution containing 1 mole of solute dissolved in 1000 g of water has the lowest freezing point? • C2H5OH(aq) • NaCl(aq) • KOH • 4) CaCl2 Be careful! What if the question asked which solution has the highest freezing point?

  12. Of the following solutions, the one that will freeze at the lowest temperature contains 1 mole of nonvolatile solute dissolved in 1) 250 g of solvent 2) 500 g of solvent 3) 750 g of solvent 4) 1000 g of solvent

  13. Which solute, when added to 1000 g of water, will produce a solution with the highest boiling point? 1) 29 g of NaCl 2) 58 g of NaCl 3) 31 g of C2H6O2 4) 62 g of C2H6O2 1 mole of NaCl → 2 moles of ions 1 mole of C2H6O2 → 1 mole of molecules

  14. Which solution will freeze at the lowest temperature? 1) 1 g of NaCl dissolved per 100 g of H2O 2) 1 g of NaCl dissolved per 1000 g of H2O • 1 g of C12H22O11 dissolved per 100 g of H2O 4) 1 g of C12H22O11 dissolved per 1000 g of H2O

  15. Which solution will freeze at the lowest temperature? 1) 1 g of NaCl dissolved per 100 g of H2O __1 g____ = 0.017 mol  0.034 mol of ions 58.8 g/mol 3) 1 g of C12H22O11 dissolved per 100 g of H2O __1 g___ = 0.0043 mol of molecules 232 g mol

  16. Effect of NonvolatileSolute • Boiling Point Elevation • Freezing Point Depression • The more particles, the bigger the effect!

  17. Applications of colligative properties Salting roads in the winter time Using salted ice to make ice cream

More Related