AP Biology Unit 1

Solvent

Solvent

Substance that can dissolve another

Solute

Part of a solution that is dissolved by the solvent

Polar

When electrons are unevenly distributed in a covalent bond

Non-polar

When electrons are evenly distributed in a covalent bond

Cohesion

attraction between identical molecules

Adhesion

attraction between molecules of different substances

Specific Heat

heat energy needed to increase the temperature of the given mass of any substance by a given amount

Density

whether something floats or sinks; MASS/VOLUME

Heat of Vaporization

The amount of energy needed to change one gram of a liquid substance to a gas at constant temperature

Macromolecules

Large molecules that contain many smaller molecules

Water

H2O; “Universal Solvent” - Dissolves many solutes

Properties of Water

• Cohesion, Adhesion

• “universal solvent”

• solid form less dense than liquid form

• high specific heat (4.18 J)

• high boiling point (100 C or 212 F)

• surface tension

HBF

Weak chemical bonds (strong intermolecular forces)

Formation of HBF

Formed when partial charges resulting from polar molecules attract/are attracted to each other

Example of Hydrogen bonding forces

cohesion between water molecules are a result of hydrogen bonds

Evaporative Cooling

When people sweat, the water absorbs the body’s excessive heat and evaporates, cooling the body

Result of HBF

high surface tension

Water structure

bent due to polarity; <109.5^o (approximately 104.5)