The Chemistry of Life ACIDS AND BASES Mrs. MacWilliams Academic Biology

ACIDS A. ACIDS- release H+ (hydrogen) ions in solution; (HX) Hydrogen always first 1. Common acids - chemical property a.) HCl = Hydrochloric acid - reacts with iron (muriatic acid) b.) HF = Hydrofluoric - reacts with glass c.) HBr = Hydrobromic - treats pool water d.) H2SO4 = Sulfuric - removes water from human tissue; in car batteries e.) HNO3 = Nitric - dissolves copper 2. Weak acids have a sour taste (ex. Lemon juice) 3. H+ is the proton and makes an acid an acid

BASES B. BASES- release OH- (hydroxide) ions in solution; (MOH) Hydroxide always in the back 1. Common Bases - chemical property a) NaOH = sodium hydroxide - turns fat into soap (ex. Lye, Drano) (Movie “Cube Zero” melting man scene) b.) KOH = Potassium hydroxide - used to "sweeten" acidic solids; made from ashes of burnt wood (potash) 2. Weak bases have a bitter or sweet taste 3. OH- is the hydroxide which makes a base a base

ACIDS AND BASES C. Dangers to the eye Acids reacts with the protein surface of the eye. A cornea transplant can help if there is damage 2. Bases dissolve the humors of the eyes and react with the rods and cones. This causes permanent damage or 100% blindness.

pH SCALE D. Measuring strengths of weak acids and bases 1. The pH scale is used to measure the strengths of acids and bases 2. Stomach acid (HCl) pH = 1 3. Blood pH = 7.4 4. Water pH = 7 (neutral) *H2O is the same as HOH (H+ acid & OH- hydroxide) 5. Household ammonia = NH3 -Ammonia is a base because it accepts a H ion and becomes NH4-

pH paper 6. Litmus paper- measures acids and bases RBB = Red to Blue = Base red to red = acid or neutral BRA = Blue to Red = Acid blue to blue = base or neutral

E. Buffers Human body pH needs to be kept between 6.5 – 7.5 pH It is important to maintain HOMEOSTASIS! pH too high or low affects chemical reactions in your body’s cells Buffers- weak acids/bases that react with strong acids/bases to prevent sharp sudden changes in pH. Example- blood pH = 7.4. Buffers such as bicarbonate and phosphate ions keep blood pH in homeostasis