Chemistry

Polar Molecules

Molecules that have an uneven distribution of charge, resulting in an asymmetrical shape or bond dipoles that do not cancel out.

Nonpolar Molecules

Molecules that have an even distribution of charge, resulting in a symmetrical shape or bond dipoles that cancel out.

Electronegativity

The ability of an atom to attract shared electrons in a bond.

Impact of large differences in electronegativity

Leads to Ionic bonds.

Impact of moderate differences in electronegativity

Leads to Polar covalent bonds.

Impact of small or no differences in electronegativity

Leads to Nonpolar covalent bonds.

What type of molecules dissolve in water?

Polar molecules and ionic compounds dissolve in water.

Why do some molecules dissolve in water while others don’t?

Molecules dissolve in water if they can form hydrogen bonds or interact with water’s polarity; nonpolar molecules don’t dissolve because they lack charges.

Cohesion (in terms of water)

Water molecules stick together, contributing to surface tension.

Adhesion (in terms of water)

Water sticks to other surfaces.

High specific heat (of water)

Water resists temperature changes.

High heat of vaporization (of water)

Water requires a lot of energy to evaporate.

Expansion upon freezing (of water)

Ice is less dense than liquid water.

Solvent properties of water

Water dissolves many polar and ionic substances.

Solubility

How well something dissolves in a liquid.

Solute

The thing being dissolved (e.g., sugar).

Solvent

The liquid that dissolves the solute (e.g., water)

Surface Tension

The "skin" on a liquid's surface caused by molecules sticking together.