Chem 120 06 Solutions and Properties

Slide 1 :Chapter 06 Solutions


Slide 2 :Properties of Solutions Solution – a homogeneous (or uniform) mixture of two or more substances. - composed of one or more solutes, dissolved in a solvent. Solute – is a compound of a solution that is present in lesser quantity than the solvent. Solvent – is the solution component present in the largest quantity.(ex. sugar(solute) and water(solvent) solution)


Slide 3 :Properties of Solutions General Properties of Solutions Clear and transparent No visible particles of solute May be colored or colorless Homogenous throughout Solute cannot be isolated by filtration Particle size of the solute is about the same as that of the solvent (Particles with diameters of 1 x 10-9 m (1 nm) Types of Solutes Based on its Electrical Conducting Properties Electrolytes – able to conduct electricity when dissolved in solution (soluble ionic compounds like NaCl). Nonelectrolytes – unable to conduct electricity when dissolved in solution (molecular solutes like glucose)


Slide 4 :Colloids and Suspensions Colloidal Suspension Consists of solute particles distributed throughout a solvent. Distribution is not completely homogenous owing to the size of colloidal particles Particles with diameters of 2 x 10-7 m (200 nm). Particles larger than 200nm will precipitate out. Colloidal particles large enough to scatter light (Tyndall Effect) Suspension A heterogeneous mixture that contains particles much larger than a colloidal suspension Overtime these particles may settle, forming a second phase. Suspension is not a true solution, nor is it a precipitate.


Slide 5 :Factors Affecting Solubility Identity of the solute and the solvent (like dissolves like) Temperature Pressure Surface Area Saturated solution – when a solution contains all the solute that can be dissolved at a particular temperature. Supersaturated solution - a solution that contains more solute than it can actually hold


Slide 6 :Factors Affecting Solubility Solubility of Gases Henry’s Law states that “The number of moles of a gas dissolved in a liquid at a given temperature is proportional to the partial pressure of the gas.” Gas solubility is directly proportional to the pressure of the gas.


Slide 7 :Concentration of Solutions: Concentrations Based on Mass Weight/Volume Percent


Slide 8 :Example 6.1 Calculate the percent composition, or % (W/V) of 3.00 x 102 mL of solution containing 15.0 g of glucose 5.00% (W/V) glucose Calculating Weight/Volume Percent


Slide 9 :Example 6.2 Calculate the number of grams of NaCl in 5.00 x 102 mL of a 10.0% (w/v)solution. X = 50.0 g NaCl Calculating the Weight of Solute from a Weight/Volume Percent


Slide 10 :Concentration of Solutions: Concentrations Based on Mass Weight/Weight Percent


Slide 11 :Example 6.3 Calculate the % (W/W) of platinum in a gold ring that contains 14.00 g of gold and 4.500 g platinum %(W/W) = 24.32% Calculating the Weight of Solute from a Weight/Volume Percent


Slide 12 :Concentration of Solutions: Concentrations Based on Mass Parts Per Thousand (ppt) and Parts Per Million (ppm)


Slide 13 :Example 6.4 A 1.00 g sample of stream water was found to contain 1.0 x 10-6 g lead. Calculate the concentration of lead in the stream water in units of % (W/W), ppt, and ppm. Which is the most suitable unit? % (W/W) = 1.0 X 10-4 % ppt = 1.0 x 10-3 ppt ppm = 1.0 ppm Calculating ppt and ppm


Slide 14 :Concentrations of Solutions: Moles and Equivalents Molarity


Slide 15 :Example 6.5 Calculate the molarity of 2.0 L of solution containing 5.0 mol NaOH. MNaOH = 2.5 M Calculating Molarity from Moles


Slide 16 :Example 6.6 If 5.00 g glucose are dissolved in 1.00 x 102 mL of solution, calculate the molarity, M, of the glucose solution. Mglucose = 2.78 x 10-1 M Calculating Molarity from Mass


Slide 17 :Example 6.7 Calculate the volume of a 0.750 M sulfuric acid (H2SO4) solution containing 0.120 mol of solute. 0.160 L Calculating Volume from Molarity


Slide 18 :Concentrations of Solutions: Moles and Equivalents Dilution


Slide 19 :Example 6.8 Calculate the molarity of a solution made by diluting 0.050 L of 0.10 M HCl solution to a volume of 1.0 L. 0.0050 M HCl Calculating Molarity After Dilution


Slide 20 :Example 6.9 Calculate the volume, in liters, of water that must be added to dilute 20.0 mL of 12.0 M HCl to 0.100 M HCl 2.40 L Solution Calculating a Dilution Volume


Slide 21 :Concentrations of Solutions: Moles and Equivalents Representation of Concentration of Ions in Solution Equivalents One equivalent of an ion is the number of grams of the ion corresponding to Avogadro’s number of electrical charges. 1 mol Na+ = 1 eq Na+ 1 mol Ca2+ = 2 eq Ca2+ 1 mol (PO4)3- = 3 eq (PO4)3- mol/L ↔ eq/L ↔ meq/L


Slide 22 :Example 6.10 Calculate the number of equivalents per liter (eq/L) of phosphate ion, PO43-, in a solution that is 5.0 x 10-3 M phosphate. 1.50 x 10-2 eq PO43-/L Calculating Ion Concentration


Slide 23 :Colligative Properties Colligative Properties – are solution properties that depend on the concentration of the solute particles, rather than the identity of the solute. Colligative Properties of Solution Vapor Pressure Lowering Freezing Point Depression Boiling Point Elevation Osmotic Pressure


Slide 24 :Colligative Properties Vapor Pressure Lowering Raoult’s Law states that “when a nonvolatile solute is added to a solvent, the vapor pressure of the solvent decreases in proportion to the concentration of the solute.”


Slide 25 :Colligative Properties Freezing Point Depression When a nonvolatile solute is added to a solvent, the freezing point of the resulting solution decreases ( a lower temperature is required to convert the liquid to a solid) Boiling Point Elevation When a nonvolatile solute is added to a solvent, the boiling point of the resulting solution increases (a higher temperature is required to convert the liquid to a gas)


Slide 26 :Colligative Properties Osmotic Pressure Semipermeable membranes – allow the solvent, but not the solute, to diffuse from one side of the membrane to the other. (cellophane, cell membranes ,etc..) Osmosis – movement of solvent from a less concentrated to a more concentrated solution through a semipermeable membrane. Osmotic Pressure – is the amount of pressure required to stop the flow of solvent from a lesser concentration to a higher concentration.


Slide 27 :Example 6.11 Determine the osmolarity of 5.0 x 10-3 M Na3PO4. 2.0 x 10-2 osmol Calculating Osmolarity


Slide 28 :Example 6.12 Calculate the osmotic pressure of a 5.0 x 10-2 M solution of NaCl at 25°C (298 K). π = 2.4 atm Calculating Osmotic Pressure


Slide 29 :Example 6.13 Sucrose is a common sugar and we know that it is used as a sweetener when dissolved in many beverages. What does this allow us to predict about the structure of sucrose? Sucrose is a polar compound Predicting the structure from observable properties


Slide 30 :Example 6.14 A typical concentration of calcium ion in blood plasma is 4 meq/L. Represent this concentration in moles/L. 2 x 10-3 mol Ca2+/L Calculating Electrolyte Concentrations


Slide 31 :Osmosis Diffusion of water (solvent) through a semipermeable membrane from less conc’d to a more conc’d sol’n. Prunes (more conc’d) put in water (less conc’d) will swell. Cucumber (less conc’d) placed in a concentrated salt solution (more conc’d), Cucumber shrinks and becomes pickle. Why do sailors (less conc’d) die of dehydration when they drink salt water (more conc’d)? Osmosis


Slide 32 :The separation of a solution from a colloid by means of a semipermeable membrane is called electrolysis osmosis dialysis neutralization


Slide 33 :Osmotic Pressure Pressure exerted during osmotic flow Regulation of fluid and electrolyte balance in the body Osmolarity (osmol) Body fluids have an osmolarity of 300 mOsmol A cardioplegic solution (used for cardiac installation during open-heart surgery) has 280 mOsmol/L Osmotic pressure (π) π = MRT Where M = molarity; R = 0.0821 Latm/molK; T = Kelvin temperature Reverse Osmosis Water moves from high conc to low conc (reverse of diffusion) Used in desalination of seawater


Slide 34 :Isotonic Solutions 2 solutions that have the same solute conc’n Solutions isotonic with blood 0.9% NaCl sol’n (physiologic saline solution) 5.5 % glucose solution (dextrose) PSS can be administered under the ff conditions: Dehydrated Lost considerable fluid (hemorrhage) To prevent postoperative shock Isotonic Solutions


Slide 35 :Hypotonic Solutions A sol’n that contains a lower solute concentration than that of another sol’n Solutions hypotonic with blood Distilled water Tap water The rbc will burst (hemolysis) Not usually used for blood transfusions Hypotonic Solutions


Slide 36 :Hypertonic Solutions A sol’n that contains a higher solute concentration than that of another sol’n Solutions hypertonic with blood 5 % NaCl solution 10% C6H12O6 solution The rbc will shrink (plasmolysis) Saline cathartics (a) MgSO4, (b) milk of magnesia, and (c) magnesium citrate  laxatives solute conc’n in (hypertonic), water will diffuse  (watery stool) Caution: dehydration Used to rid the body of excess fluid  Diuretics Hypertonic Solutions


Slide 37 :A solution that has a higher salt concentration than the blood is said to be _____. isotonic hypertonic hypotonic normal A solution that can cause plasmolysis is ______. isotonic hypotonic hypertonic normal


Slide 44 :Short Quiz on Solutions A solution contains 1.65 g of NaF in a total volume of 150.0 mL. What is its concentration expressed as % (W/V)?  What is the molarity of 50.0 mL of a 0.660 M NaOH solution after it has been diluted to 450.0 mL? Calculate the osmotic pressure of a 6.0 x 10-2 M solution of NaCl at 20°C (293 K).