Chapter 14 Solutions

Types of Mixtures Heterogeneous- do not blend smoothly throughout Colloids- Intermediate sized particles that do not settle out IMF and electrostatic forces keep particles intermixed Brownian Motion- jerky random motion observed in particles. A result of the collisions of particles in a colloid that keep the particles dispersed. Suspensions- particles settle out Thixotropic Mixtures- The solid that settles from a suspensions flows like a liquid when disturbed (paint)

Tyndall Effect You can tell the difference between a colloid and a solution by looking for the Tyndall effect Colloids- Particles are large enough to scatter light Solutions- Particles are so small that they do not scatter light

Types of Mixtures Homogeneous- Composition is the same throughout Liquid solutions are most common, but there are gas and solid solutions as well Solute- substance that is dissolved Solvent- substance that does the dissolving (is in greater amounts) Soluble- when a substance is able to be dissolved in a solvent Miscible- When two liquids can dissolve into each other

Terms for Solutions Insoluble- when a solid will not dissolve in a solvent Immiscible- when two liquids can not be dissolved into each other Solubility- Defined as the maximum amount of solute a solvent can hold at any given temperature

Factors Affecting Solvation Solvation – the process of surrounding solute particles with solvent particles to form a solution Affected by: Temperature Pressure Polarity

Factors That Affect Solvation Agitation – stirring or shaking Surface Area – increased surface area speeds up solvation Temperature – higher temperatures allow more solid to dissolve in solution

Types of Solutions Unsaturated Solution– contains less dissolved solute than it can hold Saturated Solution – contains the maximum amount of dissolved solute for a given amount of solvent Supersaturated Solution – contains more dissolved solute than a saturated solution Highly unstable

Supersaturated Solutions Made by dissolving solute at high temperatures, then cooling so the solute stays dissolved. Disturbance of solution will cause excess solute to crystallize in solution until the solution is saturated. ROCK CANDY!

Solubility Graphs Shows the solubility for a substance dependent on temperature. Any point on the line represents a saturated solution. Saturated solution Supersaturated solution Unsaturated solution

Supersaturated Saturated Unsaturated

At 50 degrees Celsius, 30 grams of KClO3 is dissolved in solution, what type of solution is this? At 60 degrees Celsius, 70 grams of Pb(NO3)2 is dissolved in solution, what type of solution is this? How many grams of KCl can dissolve in 200 grams of H2O at 10 degrees Celsius?

Concentration of Solutions Molarity- (M) moles of solute dissolved per liter of solution M is read as molar Molarity (M) = moles of solute /liter of solution Diluting a solution- to make a less concentrated solution, you take an amount of moles from the more concentrated sample and add water until you reach the desired concentration. Dilution Equation: M1V1= M2V2

Concentration of Solutions What volume of a 3.00 M KI stock solution would you use to make 0.300 L of a 1.25 M KI solution? How many mL of 5.0 M H2SO4 stock solution would you need to prepare 100.0 mL of 0.25 M H2SO4?

In a solution, there are attractions between Solute-solute particles Solvent-solvent particles Solute-solvent particles When these attractive forces are greater than solute-solute forces, a substance dissolves!

Polarity: “Like Dissolves Like” Polar substances dissolve in other polar substances Nonpolar substances dissolve in other nonpolar substances

Energy Breaking bonds requires energy Forming bonds releases energy Overcome solute attractive forces Overcome solvent attractive forces Forming bonds releases energy Attraction of solute-solvent particles Heat of Solution – overall energy change that occurs during solution formation Endothermic – energy is absorbed (feels cold) Exothermic – energy is released (feels hot)

Solubility of Gases Soluble at low temperature Particles have less kinetic energy and therefore cannot escape solution as easily Soluble at high pressure Gases above solution push down on the solution and keep gas particles in. Soda

Henry’s Law Solubility (S) is directly proportional to pressure (P) S1 =