AP Biology terms Unit 2

Adhesion

The attraction between different types of molecules. It occurs when molecules of one substance interact with molecules of another substance.

Calorie

A unit of measurement for energy, specifically the amount of heat required to raise the temperature of one gram of water by one degree Celsius.

Capillary Action

The ability of a liquid to flow in narrow spaces against gravity due to the intermolecular forces of adhesion and cohesion.

Cohesion

The attraction between molecules of the same substance, which helps them stick together.

Covalent Bond

A chemical bond formed by the sharing of electrons pairs between two atoms.

Dehydration Synthesis

A chemical reaction where two molecules are joined together with the removal of a water molecule.

Evaporation

The process where liquid water turns into water vapor due to the addition of heat energy.

Heat of Vaporization

The amount of energy required to convert a liquid into a gas at its boiling point.

Heat of Fusion

The amount of energy required to change a substance from a solid to a liquid at its melting point.

Hydrogen Bond

A weak to moderate attractive force between a hydrogen atom covalently bonded to a more electronegative atom and another electronegative atom.

Hydrolysis

A chemical reaction in which water breaks bonds between molecules, splitting them into smaller units.

Hydroxide Ion

(OH-) is a negatively charged ion made up of one oxygen atom and one hydrogen atom.

Monomer

A small molecule with partial positive and negative charges.

Polar Covalent Bond

A type of chemical bond where electrons are shared unequally between two atoms, creating a molecule with partial positive and negative charges.

Polarity

The distribution of electrical charges over the atoms joined by a bond. Polar molecules have regions of partial positive and negative charges.

Polymer

A large molecule composed of repeating subunits called monomers.

Solute

A substance that is dissolved in a solvent to form a solution.

Specific Heat Capacity

The amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius.

Sphere of Hydration

A shell of water molecules surrounding an ion or polar molecule when it is dissolved in water.

Surface tension

The cohesive force at the surface of a liquid that makes it behave like an elastic sheet.