Solutions Classification of Matter MATTER Mixtures a physical

Solutions!

Classification of Matter MATTER

Mixtures = a physical blend of 2 or more components - 2 types: (1) Homogenous Mixture = ______________ - Homogenous Aqueous Mixture: ________ (2) Heterogenous Mixture = ______________ - Heterogenous Aqueous Mixtures: Suspensions Colloids

Separating Physical Mixtures 1. ) Filtration =______________________________________________________

Solutions = a homogenous mixture of substances in the same physical state **We will be discussing aqueous solutions mostly. ** __________ Solvent =____________ Solute = ____________ can be atoms, ions, or molecules

How do solutions form? http: //www. chem. iastate. edu/group/Gr eenbowe/sections/projectfolder/flashfil es/thermochem/solution. Salt. html When an ionic compound dissolves in water: **solvation = _____________________ http: //www. mhhe. com/ph yssci/chemistry/essential chemistry/flash/molvie 1. s wf

- Polar compounds can also readily dissolve in water. - Nonpolar compounds cannot dissolve in water. Why not? **But…. nonpolar compounds can dissolve in ______ solvents. “_____ dissolves ____!” ________ compounds will dissolve in a polar solvent, but not a nonpolar solvent. _____ compounds will dissolved in a nonpolar solvent, but not a polar solvent.

- Electrolyte = _________________________________________ **All ionic compounds are electrolytes because: ____________________ - Nonelectrolyte = _________________________________________ **Most compounds are nonelectrolytes because: _____________________

Factors Affecting How Fast Particles Dissolve 1. ) Stirring makes compounds dissolve faster. 2. ) Higher temperatures make compounds dissolve faster. 3. ) Smaller-sized particles dissolve faster.

Solubility - Solubility = ___________________________________________ - usually expressed in grams of solute per 100 g of solvent - Factors Affecting Solubility 1. ) Nature of solute & solvent: **Remember: “Like dissolves like. ”**

2. ) Temperature: - As temperature in water. , most solids become ____ soluble , most gases become ____ soluble 3. ) Pressure: - Pressure has little to no effect on solubility of liquids & solids. - As pressure , solubility of gases in liquids ______

Solubility Curve - Shows the relationship of grams of solute that may be dissolved at various temperatures. - Each line represents the maximum amount of that substance that can be dissolved at a given temperature. - Lines show an increase in the solubility of solids as temperature increases, and a decrease in the solubility of gases as temperature increases.

Sample Individual Solubility Curve- Potassium nitrite Saturated Solution: = contains the maximum amount of solute for a given quantity of solvent at a constant temperature & pressure if additional solute is added, it will not dissolve; rather it will precipitate out Unsaturated Solution: = a solution that contains less solute than a saturated solution at a given temperature & pressure if additional solute is added, it will dissolve Supersaturated Solution: = contains more solute than it can theoretically hold at a given temperature crystallization will be initiate if a very small “seed crystal” of solute is added **very unstable** http: //www. metacafe. com/watch/4 04010/rapid_crystallization_supers aturated_solution_demo/

Colligative Properties of Solutions Colligative Property = ________________________ Vapor Pressure Lowering Boiling Point Elevation Freezing Point Depression

Vapor Pressure Lowering Remember: Vapor pressure = _________________ **A solution always has a lower vapor pressure than the pure solvent. ** Why?

Boiling Point Elevation Remember: A low vapor pressure means more energy is needed to get the substance to boiling (vapor pressure = atmospheric pressure). So…. . **A solution always has a higher boiling point than the pure solvent. **

Freezing Point Depression **A solution always has a lower freezing point than the pure solvent. ** Why? ? ? Vs.

The magnitude of a colligative property change is proportional to the # of solute particles dissolved in the solvent. So, the greater the # of particles: the lower the vapor pressure goes the higher the boiling point goes the lower the freezing point goes Ionic solids, therefore, produce a greater change in colligative properties: C 6 H 12 O 6 (s) C 6 H 12 O 6 (aq) Na. Cl (s) Na+(aq) + Cl-(aq) Ca. Cl 2(s) Ca +(aq) + 2 Cl-(aq)