1. An unique substances that cannot be broken down into smaller substances by ordinary chemical methods
1.1. molecule
1.2. compound
1.2.1. contains 2 atoms of the same element
1.2.1.1. Example: O2
1.2.2. substance that is composed from two or more different elements
1.2.2.1. inorganic
1.2.2.1.1. no carbon
1.2.2.2. biologically important
1.2.2.2.1. organic
1.2.2.2.2. H2O
1.2.2.2.3. organic macromolecules
1.3. solutions
1.3.1. solute + solvent
1.3.1.1. water is the universal solvent
1.3.2. pH
1.3.2.1. acid
1.3.2.1.1. pH < 7
1.3.2.1.2. H+ ions > OH- ions
1.3.2.1.3. proton donor
1.3.2.2. base
1.3.2.2.1. pH > 7
1.3.2.2.2. H+ ions < OH- ions
1.3.2.2.3. proton acceptor
1.3.2.3. neutral
1.3.2.3.1. pH = 7
1.3.2.3.2. H+ ions = OH- ions
1.3.2.4. buffer
1.3.2.4.1. stabilize pH in a solution
1.3.2.4.2. made from a weak acid and a weak base (buffer pair)
1.3.2.4.3. in blood bicarbonate ion (HCO3-) and carbonic acid (H2CO3) stabilize pH
2. most common in biological systems (96.1%)
2.1. Hydrogen H
2.2. Carbon C
2.3. Nitrogen N
2.4. Oxygen O
2.5. Sulfur S
3. Compose all Matter
3.1. Anything that has mass and takes up space
3.2. 3 states
3.2.1. solid
3.2.2. Liquid
3.2.3. gasses