General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 1 Chapter 8 Solutions 8.6 Properties of Solutions

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 2 Solutions  contain small particles (ions or molecules)  are transparent  do not separate, even by filtration or through a semipermeable membrane  do not scatter light

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 3 Colloids  have medium-sized particles  cannot be separated by filtration  can be separated by semipermeable membranes  scatter light

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 4 Examples of Colloids

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 5 Suspensions  have very large particles  settle out  can be separated by filtration  must be stirred to stay suspended Examples: blood platelets, muddy water, and calamine lotion

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 6 Solutions, Colloids, and Suspensions

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 7 Comparison of Solutions, Colloids, and Suspensions

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 8 Learning Check A mixture that has solute particles that do not settle out but are too large to pass through a semipermeable membrane is called a 1) solution 2) colloid 3) suspension

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 9 Solution A mixture that has solute particles that do not settle out but are too large to pass through a semipermeable membrane is called a 2) colloid

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Colligative Properties Colligative properties  are changes in the properties of a solvent when solute particles are added  depend on the number of solute particles in solution  involve the lowering of freezing point  involve an increase in the boiling point 10

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Freezing Point Lowering and Boiling Point Elevation When 1 mole of solute particles is added to 1000 g of water, the  freezing point of water decreases by 1.86 °C (from 0 °C to –1.86 °C)  boiling point of water increases by 0.52 °C (from 100 °C to °C) 11

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Moles of Particles The number of moles of particles depends on the type of solute:  nonelectrolytes dissolve as molecules 1 mole of nonelectrolyte = 1 mole of particles in water  strong electrolytes dissolve as ions 1 mole of electrolyte = 2 to 4 moles of particles in water 12

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Effect of Solute Particles 13

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Learning Check A 1000-g sample of water contains 0.50 mole of Na 3 PO 4. What are the new freezing point (FP) and boiling point (BP) of the solution? 1) FP  1.86 °C; BP °C 2) FP  3.72 °C; BP °C 3) FP  7.44 °C; BP °C 14

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Solution A 1000-g sample of water contains 0.50 mole of Na 3 PO 4. What are the new freezing point (FP) and boiling point (BP) of the solution? 2) FP  3.72 °C; BP °C Na 3 PO 4 3Na + + PO mole 1.5 moles 0.5 mole Total moles of solute = 2.0 moles FP = 0 °C – 2(1.86 °C) = 0 °C – 3.72 °C = –3.72 °C BP = 0 °C + 2(0.52 °C) = 0 °C °C = °C 15

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 16 Osmosis In osmosis,  water (solvent) flows from the lower solute concentration into the higher solute concentration  the level of the solution with the higher solute concentration rises  the concentrations of the two solutions become equal with time

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 17 Example of Osmosis A semipermeable membrane separates a 4% starch solution from a 10% starch solution. Starch is a colloid and cannot pass through the membrane, but water can. What happens? semipermeable membrane 10% starch4% starch H2OH2O

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 18 Example of Osmosis (continued)  The 10% starch solution is diluted by the flow of water out of the 4% solution, and its volume increases.  The 4% solution loses water, and its volume decreases.  Eventually, the water flow between the two becomes equal. 7% starch H2OH2O

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 19 Osmotic Pressure Osmotic pressure  is produced by the solute particles dissolved in a solution  is the pressure that prevents the flow of additional water into the more concentrated solution  increases as the number of dissolved particles in the solution increases

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 20 Learning Check A semipermeable membrane separates a 10% (m/v) starch solution (A) from a 5% (m/v) starch solution (B). If starch is a colloid, fill in the blanks in the statements below. 1. Solution ____ has the greater osmotic pressure. 2. Water initially flows from ___ into ___. 3. The level of solution ____ will be lower.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 21 Solution A semipermeable membrane separates a 10% (m/v) starch solution (A) from a 5% (m/v) starch solution (B). If starch is a colloid, fill in the blanks in the statements below. 1. Solution A has the greater osmotic pressure. 2. Water initially flows from B into A. 3. The level of solution B will be lower.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 22 Osmotic Pressure of the Blood Red blood cells  have cell walls that are semipermeable membranes  maintain an osmotic pressure that cannot change without damage occuring  must maintain an equal flow of water between the red blood cell and its surrounding environment

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 23 Isotonic Solutions An isotonic solution  exerts the same osmotic pressure as red blood cells  is known as a “physiological solution”  of 5.0% (m/v) glucose or 0.9% (m/v) NaCl is used medically because each has a solute concentration equal to the osmotic pressure equal to red blood cells

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 24 Hypotonic Solutions A hypotonic solution  has a lower osmotic pressure than red blood cells (RBCs)  has a lower concentration than physiological solutions  causes water to flow into RBCs  causes hemolysis (RBCs swell and may burst)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 25 Hypertonic Solutions A hypertonic solution  has a higher osmotic pressure than RBCs  has a higher concentration than physiological solutions  causes water to flow out of RBCs  causes crenation (RBCs shrink in size)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 26 Dialysis In dialysis,  solvent and small solute particles pass through an artificial membrane  large particles are retained inside  waste particles such as urea from blood are removed using hemodialysis (artificial kidney)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 27 Learning Check Indicate if each of the following solutions is 1) isotonic 2) hypotonic 3) hypertonic A. ____ 2% (m/v) NaCl solution B. ____ 1% (m/v) glucose solution C. ____ 0.5% (m/v) NaCl solution D. ____ 5% (m/v) glucose solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 28 Solution Indicate if each of the following solutions is 1) isotonic 2) hypotonic 3) hypertonic A. _3_ 2% (m/v) NaCl solution B. _2_ 1% (m/v) glucose solution C. _2_ 0.5% (m/v) NaCl solution D. _1_ 5% (m/v) glucose solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 29 Learning Check When placed in each of the following, indicate if a red blood cell will 1) not change 2) hemolyze 3) crenate A. ____ 5% (m/v) glucose solution B. ____ 1% (m/v) glucose solution C. ____ 0.5% (m/v) NaCl solution D. ____ 2% (m/v) NaCl solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 30 Solution When placed in each of the following, indicate if a red blood cell will 1) not change 2) hemolyze 3) crenate A. _1_ 5%(m/v) glucose solution B. _2_ 1%(m/v) glucose solution C. _2_ 0.5%(m/v) NaCl solution D. _3_ 2%(m/v) NaCl solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 31 Hemodialysis  When the kidneys fail, an artificial kidney uses hemodialysis to remove waste particles such as urea from blood.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 32 Learning Check Each of the following mixtures is placed in a dialyzing bag and immersed in pure water.Which substance, if any, will be found in the water outside the bag? A. 10% (m/v) KCl solution B. 5% (m/v) starch solution C. 5% (m/v) NaCl and 5% (m/v) starch solutions

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 33 Solution Each of the following mixtures is placed in a dialyzing bag and immersed in pure water.Which substance, if any, will be found in the water outside the bag? A. 10%(m/v) KCl solution:KCl ( K +, Cl − ) B. 5%(m/v) starch solution: None, starch is retained. C. 5%(m/v) NaCl and 5%(m/v) starch solutions: NaCl (Na +, Cl − ) will be found in the water outside the bag, but the starch is retained inside the bag.