Basic Chemistry and Water

A. Atoms – basic unit of matter Basic Chemistry A. Atoms – basic unit of matter 1. Composed of a nucleus containing protons (+ charge) and neutrons (0/neutral charge) surrounded by a cloud of electrons (-charge)

B. Element – pure substance of one type of atom

C. Compounds – two or more elements chemically combined (bonded)

II. Water A. Polarity - uneven distribution of electrons around a molecule (causes it to have different charges on different sides of the molecule)

B. Hydrogen Bonds - positively charged hydrogen atoms of one water molecule are attracted to the negatively charged oxygen of the next water molecule

1. An individual H bond is weak, but collectively they cause water to have many special properties

High Boiling Point Cohesion – attraction between molecules of the same substance (high surface tension)

c. Adhesion – attraction between molecules of different types

III. Solutions - Evenly distributed mixture A III. Solutions - Evenly distributed mixture A. Solute – thing that gets dissolved (salt) B. Solvent – thing that does the dissolving (water)

pH – measure of acidity and alkalinity A. 7 = neutral - equal amount of H+ and OH- (water)