Molarity

General equation

The number of moles of solute in a liter of solution

M = n/l

M = molarity

n = moles

l = liters

1. Solute (give an exaple)
2. solvent (give an example)

1. The substance dissolved in another (solvent). Salt is the solute in salt water.
2. A substance, usually a liquid, into which another substance (solute) is dissolved. Water is the solvent in iced tea.

Solution

give an example

A liquid, gas. solid phase containing 2 or more components uniformly dispersed

(air, coffee, saltwater)

Calculate the molarity when 5 moles of NaCl is dissolved in 25 liters of water

M = n/L

Molarity = 5/25

= 1/5

= 0.2 M

Calculate the moles of NaCl in 5 liters of a 2 molar solution

M = n/L

2 M = n/5 L

10 = Moles of NaCl

1. Acid Anhydride
2. Basic Anhydride

1. Non-metallic oxides which when reacted with water, form acid solutions

examples:

Co₂ + H₂O ↔ H₂CO₃

SO₃ + H₂O ↔ H₂SO₄

2. Metallic oxides which when reacted with water, form basic solutions.

examples:

Na₂ + H₂O ↔ 2NaOH

CaO + H₂O ↔ Ca(OH)₂

Why is water a good solvent for ionic compounds?

Due to hydrogen bonding, water is polar. The negative charge on the oxygen attracts a cation and the positive charge on hydrogen an anion

1. Solubility Curves
2. How do the temperature and pressure affect the solubility of a solid?

1. A curve for a given substance which shows how much dissolves in a given amount of solvent at different temperatures.
2. Solubility usually increases with increasing temperature. Pressure has little effect

1. How do temperature and pressure affect the solubility of  a gas?
2. What 3 factors affect the rate of solubility?

1. Solubility usually decreases with increasing temperature. Solubility increases in direct proportion to increase in pressure.
2. Pulverizing; stirring; heating

"Like dissolves like"

Ionic and polar solvents dissolve ionic, polar solutes.

(water dissolves salt)

Nonpolar solvents dissolve nonpolar solutes.

(acetone dissolves gasoline)

Solubility rules of (in water)

1. nitrates, acetates, chlorates
2. Na, K, and NH₄⁺ compounds
3. chlorides
4. sulfates

1. All are soluble
2. All are soluble
3. All chlorides are soluble except Ag, Hg, Pb
4. All sulfates are soluble except Pb, Ba. Sr. Ca

Solubility rules of (in water)

1. carbonates, phosphates, sulfides, silicates
2. hydorxides (OH^-)

1. All insoluble except Na, K, NH₄⁺
2. All insoluble except Na, K, NH₄⁺, Ca, Ba, Sr

1. Miscible
2. Immiscible

1. Two liquids which dissolve in each other.

 (example: water and alcohol)

2. Two liquids which do not dissolve in each other.

(example: oil and vinegar)

List some basic facts about...

Solutions

• particle size less than 1 nanometer
• clear (may be colored)
• particles don't settle
• can pass through membranes
• particles not visible

List some basic facts about...

Colloids

• particles measure 1-1000 nanometers
• particles don't pass through a membrane
• show brownain motion and the tyndall effect
• particles don't settle
• clear and pass through filter paper

List some basic facts about...

Suspensions

• no brownian motion
• don't pass through filter paper or membrane
• cloudy but particles settle on standing
• particles visible with microscope or eye

When light shone through a colloid, the individual zig-zag paths of the particles in the dispersing medium can be observed.

(like smoke in a dark theater

1. Dilute
2. Concentrated

1. Small amount of solute in the solvent
2. Large amount of solute in solvent

1. Saturated
2. Unsaturated

1. The solution is holding all the solute possible at the temperature; in the presence of undissolved solute.
2. More solute can be dissolved in the solvent at that temperature.

Write equation for:

% concentration of a solute in a solution

5% = (x/500g)(100%)

x = 25g NaCl

The number of moles of solute dissolved in 1 kg of solvent

Molality (m)= moles solute/kg solvent

Molality = moles solute/kg solvent

= 10/4 = 2.5 molal

1. Gram-equivalent weight
2. Normality

1. The amount of substance which reacts with or displaces 1 mole of H⁺ ions
2. The number of gram-equivalent weights in a liter of solution

M₁ x V₁ = M₂ x V₂

M = molarity

V = volume

(6) x (10) = (3) x V₂

V₂ = 20 L

Colligative

Properties

Vapor pressure lowering

Boiling point elevation

Freezing point depression

In H₂O solutions

1. How many °C is the freezing point depressed for each molal of solute?
2. How many °C is the boiling point elevated for each molal of solute?

1. 1.86 C for each molal particle of solute

2. 0.51 C for each molal of particles of solute

1. Hydrated crystal

2. Crystal

1. A crystal that holds a definite proportion of water in its structure

2. In a crystal structure the ions or atoms form a repeating pattern of unit cells

1. Efflorescent

2. Deliquescent

1. Hydrated crystals which lose their water of hydration on exposure to air at room temperature

(example: magnesium sulfate)

2. Hydrated crystals which absorb water from the air and become wet

(example: calcium chloride and magnesium chloride)

1. Anhydrous crystals

2. Unit cell

1. A hydrated crystal which loses its water of hydration. The pure salt loses the crystal structure and crumbles to powder.

2. The smallest portion of a crystal lattice that is repeated throughout the crystal

• Simple cubic
• face-centered cubic
• body-centered cubic
• tetragonal
• hexagonal
• monoclinic