Chemistry Unit 6

Solubilit, Concentration, pH/pOH, Colligative Properties, Acids, Bases, Neutralization, and Equilibrium.

A Solution

A homogeneous mixture of one or more solutes dissolved in a solvent.

Homogeneous Mixture

A mixture in which the composition IS uniform throughout the mixture

Heterogeneous Mixture

A mixture in which the composition is NOT uniform throughout the mixture

Three things that will help solutions/reactions form

Agitation, Temperature, Size of particles of the solute

Solute

The substance that dissolves in a solvent to produce a homogeneous mixture.

Solvent

The substance in which a solute dissolves to produce a homogeneous mixture.

Solubility

The amount of solute that can be dissolved in an given amount of solvent at a set temperature and pressure

when the max amount of solute has been reached

Saturated

Density

The mass of a substance per unit of volume

Supersaturated solution

A solution that contains more dissolved solute than required for preparing a saturated solution

Concentration of a solute

A measure of the amount of solute that is dissolved in a given quantity of solvent

Concentration = ?

Molarity

Dilution

Lowering the concentration of the solute by adding more solvet (usally H20)

Colligitave Properties

Vapor-Pressure Lowering, Freezing-Point Depression, & Boiling-Point Elevation

Vapor-Pressure

The pressure created by gas that is at equilibrium with its gas

Vapor-Pressure Lowering

Adding solute lowers the number of gas particles made by \n a liquid solution.

Freezing-Point Depression

Adding solute blocks solvent particles from gathering \n together and forming a solid.

Freezing Point

the temperature at which a substance changes to a sold

Boiling-Point Elevation

Adding solute holds particles together with more force, \n making it harder for individual particles to escape into the gas \n phase.

Boiling Point

the temperature at which a liquid turns into a gas

Molality

A measure of solute concentration in a solution (used for colligative property calculations)

Mole Fraction

The ratio of the # of moles in a solution to the total # of moles in both the solvent & solute

Acid

pH =1 - 6.9

Base

pH = 7.1 - 14

Arrhenius acids/bases

Acids produce H+ & Bases produce OH-

Bronsted-Lowry acids/bases (primary model we use)

Acids donate protons (H+) & Bases accept protons (H+)

Lewis acids/bases

Acids accept a pair of electrons & Bases donate a pair of electrons

Equation for pH

pH = -log[H+]

Equation for pOH

pOH = -log[OH-]

What does pH+pOH equal?

14

Equation for [H+]

[H+] = 10^-pH

Equation for [OH-]

[OH-] = 10^-pOH

Neutralization reactions

Whem a strong acid and a strong base react

What does a Neutralization reaction contain?

Water and a salt (such as NaCl or KCl)

Titration

A technique where a solution of known concentration is used to determine the concentration of an unknown solution.

What is the goal of titration

To find the Equivalence Point

Equivalence Point

point in titration at which the amount of titrant added is just enough to completely neutralize the solution

Half Equivalence Point

the point at which exactly half of the acid in the buffer solution has reacted with the titrant. ( [HA-]=[A-] )

Buffer Region

 A region where the pH of a solution remains constant

Le Chatelier’s Principle

If you mess with a system, it will automatically try to move back to equilibrium

Chemical Equilibrium

 A state in which the rate of the forward reaction equals the rate of the backward reaction. (aka balanced)

Concentration & Temperature Changes in Equilibrium

Increase will make it shift away, decrease will make it shift toward