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7-5.6 Distinguish between acids and bases and use indicators (including litmus paper, pH paper, and phenolphthalein) to determine their relative pH. Relevancy. Acid Rain Ppt. What do you know about acids, bases, pH?. Solute and Solvents
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7-5.6 Distinguish between acids and bases and use indicators (including litmus paper, pH paper, and phenolphthalein) to determine their relative pH.
Relevancy • Acid Rain Ppt
Solute and Solvents • The solute and solvent in a solution determine the concentration. • Concentration • Describes how much solute is present in a solution compared to the amount of solvent
(ex) 5% Hydrochloric Acid (HCl) Solution used to test a reaction on the limestone • for every 100 mL of water (solvent) there is 5 mL HCl (solute)
Acid • How to identify: • Sour taste • (ex) lemons and oranges • Reaction with some metals • (ex) zinc • Reaction to bases • Acid + Base = less acidic (increases pH) • Must have same concentration • (ex) vinegar reacting with limestone
Base • How to identify • Bitter taste • (ex) unsweetened cocoa • Feels slippery • (ex) dish detergent • Reaction to some acids • Base + Acid = less basic (lowers pH) • Must be same concentration • (ex) antacid tablet can sooth a stomach with too much acid (sometimes called alkali)
Neutral Solution • Neither an acid nor a base • (ex) pure water = pH 7
pH • pH scale • Way to measure how acidic or basic a solution is • pH range of a solution • 0 to 14 • Examples • Neutral pH of 7 (ex) pure water • Acid pH less than 7 to 0 • The lower the number (like 1) the more acidic the solution • Base pH greater than 7 to 14 • The higher the number (like 13) the more basic the solution
pH meanspercent of H+ • Hydrogen ions
Less than 7 through 0 Greater 7 through 14 1) What is the pH range of an acid? ______ 2) What is the pH range of a base? ______ 3) What two things help identify a substance as an acid? 4) What two things help identify a substance as a base? 5) What is the pH of a neutral solution?___ Tastes sour, reacts with metals Tastes bitter, feels slippery 7
Identify the substance as an acid, base, or neutral BASE ACID BASE NEUTRAL ACID
pH decreases • What happens to pH when you add a little acid to a base? • What happens to pH when you add a little base to an acid? • What happens to a solution when you add a low concentration of acid to a neutral solution? • What happens to solution when you add a low concentration of a base to a neutral solution? pH increases pH decreases, becomes a weak acid pH increases, becomes a weak base