AP bio: unit 1, module 2

Polar

A molecule that has regions of positive and negative charge.

Hydrogen bond

An interaction between a hydrogen atom with a slight positive charge and an electronegative atom of another molecule. In the case of water, hydrogen bonds form between the hydrogen atom of one water molecule and oxygen atom of another water molecule.

Cohesion

Tendency of water molecules to stick to one another due to hydrogen bonding with one another

Adhesion

The tendency of water molecules to stick to other polar or charged molecules.

Surface tension

A measure of the difficulty of breaking the surface of a liquid.

Specific heat

The amount of heat required per unit mass of a substance to raise the temperature of the mass by 1 degree Celsius.

Solvent

A substance that can dissolve another substance.

Acid

A molecule that donates H+ ions to a solution. When the concentration of hydrogen ions is greater than the concentration of hydroxide ions, the pH is acidic.

Base

A molecule that accepts H+ ions and removes them from solution. When the concentration of hydrogen ions is less than the concentration of hydroxide ions, the solution is basic or alkaline.

pH scale

A measure of the acidity of a solution. The pH scale ranges from 0 to 14 and is calculated by the negative logarithm of the hydrogen ion concentration.

Dehydration synthesis reaction

A reaction in which a water molecule is released by the two reacting molecules as a new covalent bond is formed between them. Dehydration synthesis reactions build from smaller subunits. Also called dehydration reaction.

Hydrolysis reaction

A reaction that adds water across a covalent bond and breaks the covalent bond. Hydrolysis reactions break down larger molecules into smaller, simpler molecules.