ACIDS AND BASES Angel Jane Roullo Kristylle Marie Abelardo

ACIDS :  comes from the latin word “acidus” meaning sour or tart.  have a sour taste  corrosive to metals  cause litmus to change to red  produces CO 2 gas when mixed with carbonated solutions.  conduct electricity

BASES :  Have a bitter taste  slippery to touch  cause litmus dye to turn blue  conducts electricity

ARRHENUS THEORY - Svante Arrhenus  acids – substances that when dissolved in water, increase the concentration of H + ions. -  bases – substances that when dissolved in water, increase the concentration of OH - ions.

BRONSTED-LOWRY -- Johannes Bronsted & Thomas Lowry Acid – substance (molecule or ion) that can donate a proton to another substance. Base – substance ( molecule or ion) that can accept a proton to another substance. LEWIS THEORY – G.N. Lewis  Acid – electron-pair acceptor  Base – electron-pair donor

Strong acids & bases - react with H 2 O, giving a 100% yield leaving no undisassociated molecules in solution. Weak acids & bases - only partly disassociated in aquaeous solutions and give a 10% or less yield of hydrogen ion (in acids) or hydroxide ions ( in bases) * a strong acid or base has a weak conjugate pair and vice versa.

i. % ionization- % age of ionized molecules % ionization = conc ionized/ original ionized x 100 ii. Equilibrium constant * stronger acid/ base has a larger equilibrium constant. iii. Concentration of H + & OH - ion * larger quantity of H + or OH - the stronger the acid or base.

iv. pH & Poh pH - negative logarithm of the H conc. pH = -log(H+) * neutral solution has a pH of 7 * pH of an acidic solution ( H+ > OH-) is less than 7 * pH of a basic solution ( OH- > H+ ) is greater than 7 * pH meter-measures the pH of solution

pH indicators --  used to measure pH  colored substance that itself can exist in either an acid or a base form.  they turn 1 color in an acid & another in a base.

indicator Color in acidic solution Color in basic solution litmus red blue phenolphthalein colorless pink methyl orange pink yellow

Common Applications and Uses of Acids and BAses Antacids – bases used to neutralize too much Hcl in the stomach (condition called hyperacidity) Cleaning agents – an example is hydrochloric acid. Vinegar – is an acetic acid Antiseptic eyewash – boric acid Fertilizer – ammonia Soap – sodium hydroxide