Nuclear Chemistry

Mixture

combination of two or more substances

Homogenous Mixture

Mixture that looks uniform all through out

Looks “properly mixed”

Ex. Salt water, air

Heterogenous Mixture

Mixture where different parts are not evenly mixed

You can see the different components

Ex. Oil and water, sand and water

Solutions 

Appearance: Homogenous

Particle Size: Small, < 1nm

Settling: NO

Separation: Cannot be separated by filtration

Tyndall Effect: Do not scatter light

Colloid

Appearance: Homogenous

Particle Size: Larger, 1nm - 1μm

Settling: NO

Separation: Cannot be separated through common filtration techniques

Tyndall Effect: Scatter light or can be opaque

Suspension

Appearance: Heterogenous

Particle Size: Large, > 1 μm

Settling: Yes

Separation; can be separated by filtration or centrifugation

Tyndall Effect: Scatters light

Types of Solution - Undersaturated

Solution that contains less than the maximum amount of solute that it can dissolve in a given amount of solvent at a given temperature.

Types of Solution - Saturated

Solution that contains the maximum amount of solute that it can dissolve in a given amount of solvent at a given temperature.

Types of Solution - Supersaturated

Solution that contains more than the maximum amount of solute that it can dissolve in a given amount of solvent at a given temperature.

Polar Solvent dissolution

Polar and Ionic Compounds are soluble in this type of solvent

Non Polar Solvent Dissolution

Non Polar Compounds are soluble in this type of solvent

Dissolving NaCl in Water

• When ionic NaCl dissolves in water, the Na+ and Cl− interactions of the crystal are replaced by new interactions with the solvent.

• Each ion is surrounded by water molecules, which arrange so that opposite charges are near each other.

Dissolving and Energy Changes

• Dissolving a solute in a solvent is a physical process with energy change.

• Breaking solute particles → requires energy

  (endothermic)

• Forming new forces between solute and solvent

  → releases energy (exothermic)

Applications of Hot & Cold Packs

• Breaking the seal lets salt and water mix, causing

  the salt to dissolve.

• Hot packs (CaCl2 or MgSO4) - Salt dissolves →

  releases heat → muscle pain relief (exothermic)

• Cold packs (NH4NO3) - Salt dissolves → absorbs

  heat → reduce swelling (endothermic)

Henry’s Law

The solubility of a gas in a liquid is directly proportional to its partial pressure above the liquid.

Concentrated Solution

Relatively large amount of dissolved solute

Diluted Solution 

Relatively small amount of dissolved solute

Percent weight per volume (%w/v)

Percent of volume per volume (%v/v)

Molarity (M)

Parts per million (ppm)

Dissolving Sodium Chloride in Water

When NaCl meet with H₂O

1. Water molecules surround the Na⁺ and Cl⁻ ions

2. Negative end of the water (oxygen) is attracted Na⁺

3. Positive end of water (Sodium) is attracted to Cl⁻

Separation:

• bonds are strong enough to pull Na⁺ and Cl⁻ apart from the salt crystal

• each ion is now surrounded by water molecules (hydration)

Dissolving and energy changes - “Like-Like” Bond

Requires energy

Endothermic

• Solute-solute bonds

• solvent-solvent bonds

Dissolving and energy changes - “Opposite” Bond

Doesn’t require energy

Exothermic

• Solute-Solvent bond

Application of hot packs and cold packs - Hot Pack

Pack releases heat, Patient Absorbs heat

1. Contain a solid like calcium chloride (CaCl₂) or magnesium sulfate (MgSO₄).

2. When Pack is activated, salt dissolves in water inside 

3. Energy is released and pack becomes hot

Applications of hot packs and cold packs - Cold Pack

Pack Absorbs heat, Patient releases heat

1. Contain a salt like ammonium nitrate (NH₄NO₃) or potassium chloride (KCl).

2. When Pack is activated, salt dissolves in water inside 

3. It absorbs heat from surroundings → the pack feels cold.

EFFECTS OF TEMPERATURE AND PRESSURE ON

SOLUBILITY

The solubility of solids in liquids generally increases with

temperature

Colligative Properties 

• Properties of a solution that depends on the concentration

or number of particles dissolved in a solution, but not its

identity

• Common colligative properties include:

○ Boiling Point elevation

○ Freezing Point Depression

○ Osmotic Pressure