Essay Aqueous Systems And Solutions Study Guide

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Study Guide for Aqueous Systems and Solutions Test
Chapter 15
1. Know unique properties of water and ice
a. Liquid water: high surface tension (minimizing surface area) and low vapor pressure (therefore high boiling point)
b. Ice: less dense than liquid water (due to open framework of water molecules arranged like a honeycomb) and floats (due to lower density)
2. Be able to identify solute and solvent in various types of solid, liquid and gaseous solutions
a. solvent dissolves the solute
b. solute becomes dispersed in the solvent
3. Mixtures: Homogenous and heterogenous
a. Homogenous: uniform in composition; components are evenly distributed; not easily distinguished; solute particles <1nm; stable mixtures; do not settle
b. Heterogenous: not uniform; not evenly distributed; solute particles >1 nm;
4. Know differences between solutions, colloids, suspension, and examples of each Solution

Colloid

Suspension

homogenous

heterogenous

heterogenous

ions, atoms, small molecules large molecules or particles large particles or aggregates no scattering

Tyndall effect

Tyndall effect

particles go thru filter

particles go thru filter

particles don’t go thru filter stable; doesn’t settle

stable; doesn’t settle

unstable; settles

.1­1 nm

1­1000 nm

>1000 nm

5. Understand process of solvation for both ionic and molecular substances
a. Ionic: ions in the solute break away and get surrounded by solvent molecules and dissolve completely (except when forces in solute are too strong i.e. BaSO4 and
CaCO3)
b. Molecular: the forces in the two nonpolar molecules have the same attraction ­> molecules can replace each other and form a solution
6. Electrolytes and nonelectrolytes
a. Electrolytes: conducts electricity in aqueous or molten states; mostly ionic
i.
Strong: nearly all of solute dissolved and separated into ions

ii.
Weak: only fraction of solute in the solution exists as ions
b. Nonelectrolytes: does not conduct electricity in either aqueous or molten state; mostly molecular
7. Understand that “like dissolves like” and predict if one substance will be soluble in another
a. Polar solutes dissolve in Polar solvents
b. Nonpolar solutes dissolve in Nonpolar solvents
Solution Process
1. Know factors that affect rate of dissolution
a. Surface area: smaller particles of solute ­> more exposure to solvent
b. Agitation: brings fresh solvent in contact with solute and removes newly dissolved solute from surfaces of solvent
c. Temperature: heating solvent ­> more collisions with solute
2. Understand what affects the solubility of a substance (nature of solute and solvent), T&P
a. if the attraction between solvent and solute is less than the attraction between the solvent/solute molecules, then the solution will not dissolve; most ionic solids dissolve b. solubility of ionic solutes increase as temp increases
c. pressure only affects the solubility of gases (see Henry’s Law)
3. Solution equilibrium­saturated, unsaturated, and supersaturated solutions
a. Unsaturated: not reached limit amt of solute that can be dissolved; keeps dissolving as more added
b. Saturated: max amount solute that will dissolve at that temp; ADD MORE
SOLUTE AND IT SETTLES OUT
c. Supersaturated: more solute that it should theoretically hold;
CRYSTALLIZATION OR INCREASE OF TEMP
4. Solute­solvent interactions­miscibility
a. miscible: two liquids dissolve in each other
b. immiscible: two liquids don’t dissolve in each other
5. Be able to read solubility curves to determine how much of a solute can dissolve in a given amount of solute at a specific temperature
a. temperature at bottom
b. solubility at sides
c. multiply is more than 100 mL
6. Determine if a solution is saturated, supersaturated, or unsaturated from a solubility curve
a. Saturated: on the line
b. Supersaturated: above the line
c. Unsaturated: below the line
7. Know effect of temperature on solubility
a. Solids:…