Group+9+Period+7

Chapter 8 [|Vocab link:]

Chapter 8.1 Notes:

__Solutions__

A solution is a homogeneous mixture of two or more substance. Parts of a solution: -**Solute-** (what is dissolved in a solution) the smaller part of a solution. -**Solvent-** (what the solute dissolves in) the larger part of a solution. Solutions can be gases, liquids, or solids. Named for the state of the solvent: -Solid (solution) -liquid (solution) -gas (solution) __Dissolving__

Substances in water in three ways: 1. **Dissociation** (physical change) Process in which ionic compounds seperate into ions when they dissolve Water is polar: -The negatively charged ions are attracted to positive charges in H2O -Positively charged ions are attracted to the negative charges in H2O 2. **Dispersion** (physical) The particles of the solute break into smaller pieces and spread throughout H2O. 3. **Ionization of molecular compounds** (chemical) Neutral molecules gain or lose electrons and become ions. (from atoms) - H2O + HCl - H3O + Cl

__Properties of Liquid Solutions__

Physical properties -Conductivity, freezing point, and boiling point of a solution differfrom the properties of the soution's solute and solvent. Conductivity ex. __NaCl in water__ vs. in solid form ^ions can move better (negative has more conductivity) Solute particles affect (raise or lower) the freezing point and boiling points of the solvent. ex. MgCl2 spread on ice

__Heat of Solution__

When solutions are formed, energy is either released or absorbed. -solution formation can either be exothermic or endothermic If heat is given off then it is exothermic. If heat is absorbed, the solution feels cold and is endothermic.

__Factors that affect rates of dissolving__

Stirring, surface area, and temperature. During the formation of a solution, the particles of the solute and the solvent collide. -The more collisions, the faster the rate. (compare this to chemical reaction rates from chapter 7)