Acids, Bases and Solutions

I. Solutions and Suspensions

Suspensions- is a mixture in which the particles can be seenand early separated by gravity (settling) or size (filtration).

Solutions- a well mixed mixture. You can not separate bygravity or size. Diffusion will mix the mixture so that it isuniform, given enough time. A homogeneous mixture.

Solvent- the more abundant substance in a solution. Water is the “universal solvent”.

Solute- the less abundant substance in a solution.

Whenever a solution forms, particles of the solute leave eachother and become surrounded by particles of the solvent.

Notice that the Na + ions attract the O - end of the HOH molecules

Effects of Solutes on Solutions

Solutes lower the freezing point of the solvent.

Solutes raise the boiling point of the solvent.

Concentrations and Solutions

Can be subjective:

Dilute - a little solute.

Concentrated - lots of solute.

Can be objective:

A molar solution : 6.02 X 10 23 solute items

1 Mole = 1 formula weight in 1 liter of solvent

1.5 Molar solution =

Solubility of Solutes in Solvents

Unsaturated Solution: You can add more solute and it will dissolve.

Saturated Solution: If you add more solute it will NOT dissolve.

Supersaturated Solution: Change the rules of the game.

How ?

The solubility of a substance is described as a specific solventat a specific temperature.

Changing Solubility

Temperature

Increasing the temperature of the solvent will make more roomfor the solute. This works well for solids.

Type of solvent

A gas dissolves best at colder temperatures.

Like dissolves like.

Polar and nonpolar compounds DO NOT mix well.

II. Acids and Bases

Properties of Acids

Any substance that forms hydrogen ions (H+) in water.

This is an atom of hydrogen that has lost its electron.

The number of hydrogen ions released determine if the acid isstrong or weak. This is not concentration.

Sour Taste

Reaction with Litmus paper

Turns litmus paper RED

Reaction with metals

Reaction with some metals produce hydrogen gas.

Mg, Zn, Fe

Zn + 2 HCl → ZnCl2 + H2 ↑

Metal etchings

Reaction with carbonates (limestone or chalk)

Produces a gas; Carbon dioxide (CO2)

2 HCl + CaCO3 → CaCl2 + CO2 + H2O

Properties of Bases

Any substance that forms hydroxide ions (OH-) in water.

The number of hydroxide ions released determine if the baseis strong or weak. This is not concentration.

This is a polyatomic ion that moves together as a pair.

Bitter Taste

Reaction with Litmus paper

Turns litmus paper BLUE

Slippery feel

Strong vs Concentration

How well it separates into ions in water?

Measuring Concentration (pH)

A weak acid can have a low pH (high concentration).

Acid Rain

H2O + CO2 → H2CO3

Nitrogen oxides or Sulfur oxides

Acid- Base Reactions (Neutralization Reactions)

HCl + NaOH → NaCl + H2O

HNO3 + KOH → KNO3 + H2O