Understanding Colloids, Suspensions, Osmosis, and Dialysis: Key Principles and Applications

1. Chapter 8Solutions Colloids and Suspensions Osmosis and Dialysis LecturePLUS Timberlake

2. Solutions • Have small particles (ions or molecules) • Are transparent • Do not separate • Cannot be filtered • Do not scatter light. LecturePLUS Timberlake

3. Colloids • Have medium size particles • Cannot be filtered • Separated with semipermeable membranes • Scatter light (Tyndall effect) LecturePLUS Timberlake

4. Examples of Colloids • Fog • Whipped cream • Milk • Cheese • Blood plasma • Pearls LecturePLUS Timberlake

5. Suspensions • Have very large particles • Settle out • Can be filtered • Must stir to stay suspended LecturePLUS Timberlake

6. Examples of Suspensions • Blood platelets • Muddy water • Calamine lotion LecturePLUS Timberlake

7. Osmosis • In osmosis, the solvent water moves through a semipermeable membrane • Water flows from the side with the lower solute concentration into the side with the higher solute concentration • Eventually, the concentrations of the two solutions become equal. LecturePLUS Timberlake

8. Osmosis semipermeable membrane 4% starch 10% starch H2O LecturePLUS Timberlake

9. Equilibrium is reached. water flow becomes equal 7% starch 7% starch H2OO LecturePLUS Timberlake

10. Osmotic Pressure • Produced by the number of solute particles dissolved in a solution • Equal to the pressure that would prevent the flow of additional water into the more concentrated solution • Increases as the number of dissolved particles increase LecturePLUS Timberlake

11. Osmotic Pressure of the Blood • Cell walls are semipermeable membranes • The osmotic pressure of blood cells cannot change or damage occurs. • The flow of water between a red blood cell and its surrounding environment must be equal LecturePLUS Timberlake

12. Isotonic solutions • Exert the same osmotic pressure as red blood cells. • Medically 5% glucose and 0.9% NaCl are used their solute concentrations provide an osmotic pressure equal to that of red blood cells H2O LecturePLUS Timberlake

13. Hypotonic Solutions • Lower osmotic pressure than red blood cells • Lower concentration of particles than RBCs • In a hypotonic solution, water flows into the RBC • The RBC undergoes hemolysis; it swells and may burst. H2O LecturePLUS Timberlake

14. Hypertonic Solutions • Has higher osmotic pressure than RBC • Has a higher particle concentration • In hypertonic solutions, water flows out of the RBC • The RBC shrinks in size (crenation) H2O LecturePLUS Timberlake

15. Dialysis • Occurs when solvent and small solute particles pass through a semipermeable membrane • Large particles retained inside • Hemodialysis is used medically (artificial kidney) to remove waste particles such as urea from blood LecturePLUS Timberlake