Acids, Bases and pH

Acids, Bases & pH H2O  H+ + OH- 1 water molecule in 550 million naturally dissociates (ionizes) into a Hydrogen Ion and a Hydroxide Ion Hydrogen Ion Hydroxide Ion Acid Base H2O  H+ + OH-

Acids, Bases and pH pH = “potential of Hydrogen” pH scale 0-14 Each increase of one on the pH Scale = a 10x increase in the hydrogen ions in the solution more H+ = more acidic = LOWER pH More OH- = more basic = HIGHER pH

Acidity (pH) pH 7 = neutral – H+ and OH- exactly balanced pH 0.0 - 6.99 = ACID Taste sour ex. fruit juices pH 7.01 to 14.0 = BASE Taste bitter Feel slippery ex. soaps, bleach Farther away from 7 - stronger Most life needs close to neutral, between pH 6 & 8

Buffers Weak acids / bases that react with strong acids / bases to prevent sharp, sudden changes in pH You have buffers in your body! Weak Acid Weak Base

Some Examples of Acidity Gastric Fluid = ~1.2 pH Lemon Juice = ~2.1 pH Orange Juice = ~3.6 pH Rain* = ~ 5.8 pH Distilled H2O = 7.0 pH Blood = ~ 7.2 pH Seawater = ~8.0 pH Ammonia = ~ 12.8 pH Lye = ~13.5 pH

Atoms, Molecules and Bonds Atom: smallest particle of an element protons (+) electrons (-) neutrons (no charge) Element: many of the same atoms Examples: Carbon, Hydrogen, Oxygen, Gold, Lead.

Atoms, Molecules and Bonds Compound/Molecule: Atoms combined by the formation of bonds Example: H2O, C6H12O6 Bond: Hold atoms together Release energy when broken More bonds = more energy Example: Food energy, gasoline

Atoms, Molecules and Bonds Three Types of Bonds Ionic: One atoms gives electrons to another Weak bond Dissolve in water ex. NaCl Covalent: Atoms share electrons Hold molecules together Way strong ex. O2, H2O Hydrogen: Weak Break easily ex. Between H2O molecules, within proteins