Ch. 16 Notes -- Acids and Bases

1. sour lemons Ch. 16 Notes -- Acids and Bases metals What makes something an acid? Acid Properties: (1) tastes _______-- _______________ (2) corrosive to _________ (3) contains [ ___ ] (or [ _____ ] = “_______________” ions) (4) proton ([ ___ ]) __________-- Brønsted-Lowry Theory Example: HCl + H2O  ______ + ______ H+ H3O+ hydronium H+ donor H3O+ Cl−

2. citrus aspirin vinegar DNA Examples of Common Acids: Pepsi, _________ juices, ___________, stomach acid, battery acid, _____________, ______

3. Acid Vocabulary dissociate many H2SO4 HCl • strong acid - readily ___________ to produce ______ [H+] ions in water Examples: _________, HNO3, _______ • weak acid - produces a __________ amount of [H+] ions when in water Examples: HC2H3O2 (vinegar) , _________, _________ small H2CO3 lemon juice

4. Strong Acids vs. Weak Acids

5. Indicators colors • An indicator is a chemical that will change ___________ when placed in an acidic, basic or neutral environment. Indicator Colors For Acids • litmus paper = _______ • phenolphthalein = ___________ • red cabbage juice (universal indicator) = ________ • methyl orange = _______ red clear red red

6. pH Paper : Indicator Colors Neutral Acidic Basic

7. Properties of Bases What make something a base? Base Properties: (…the opposite of acid properties) (1) tastes ________ -- ___________ peel , parsley, dark chocolate (2) feels _____________ -- ________ (3) contains [ _____ ] ions (4) proton ([H+]) ______________-- Brønsted-Lowry Theory Example: NH3 + H2O  ______ + _______ bitter banana slippery soap OH− acceptor NH4+ OH−

8. Indicator Colors for Bases blue yellow • litmus paper = _______ • methyl orange = ____________ • red cabbage juice (universal indicator) =________ • phenolphthalein = ______ blue pink phenolphthalein Acid Base

9. Common Bases ammonia antacid baking soda • Examples of Common Bases: milk of magnesia, ___________, drain cleaner, soap, blood, ____________ tablets, ___________ ________.

10. Strong Bases vs. Weak Bases dissociate many • strong base- readily __________ to produce ______ [OH−] ions in water Examples: NaOH , ________ • weak base- produces a __________ amount of [OH−] ions when in water Examples: _____ (ammonia); Mg(OH)2 (milk of magnesia) Other Vocabulary • _______________- another term for basic solutions • _______________- a substance that can act as both an acid and a base Examples: ___________ , ____________ KOH small NH3 Alkaline Amphoteric H2O HCO3−

11. Self-Ionization of Water neutral small • Pure water is _____________. It can ionize itself to form OH− and H3O+ ions in __________ amounts. H2O + H2O  H3O+ + OH− (or H2O  _______ + _______ ) • The universal indicator color is ___________ in neutral solutions. H+ OH− green self-ionization of water

12. Measuring the Amount of H+ and OH− Ions in a Solution pH concentration pOH OH− • _____ Scale- measures the _____________ of [H+] ions in a solution • _____ Scale- measures the concentration of [ ____ ] ions in a solution Formulas pH = − (log [H+]) pOH = −(log [OH−]) [H+] = 10−pH [OH−] = 10−pOH [H+] x [OH−] = 1 x 10−14 pH + pOH = 14 • With the pH scale, we have another way to define acids and bases: Acids have a pH _________7.0 Bases have a pH _________7.0 Neutral pH ___7.0 below above =

16. [H+] = 0.001 M So…pH = − (log 0.001 M) pH = 3 Practice Problems: 1) a) Calculate the pH of a 0.001 M HCl solution b) Is this an acid or a base? 2) a) What is the concentration of [H+] ions in a solution that has a pH of 8.50? b) Is this an acid or a base? Acid! [H+] = 10−pH [H+] = 10−8.5 Molar or 3.16 x 10−9 M Base!

17. pH Testing

18. Alkalinity Testing

19. Neutralization Reactions salt When an acid and base are mixed, the reaction produces _______ and ___________. • If the initial concentrations and volumes of the reactants are equal, the products will be ____________... (pH= 7.0) • All neutralization reactions are ___________ replacement reactions. water neutral double H2O HX + M(OH)  ______ + ______ MX (“Salt”)

20. Titration concentration • Mixing an acid with a base to determine a __________________ is called “titration.” • An ____________ is used to determine when neutralization has occurred. • ________________ Solution- the solution of known concentration • _________________- the point of neutralization when titrating • At the eqivalence point, the moles of [H+] ions = moles of [OH−] ions. • The “_____ Point” is when the indicator changes color. indicator Standard Equivalence Point End

21. Titration Curve

22. KNO3 H2O Practice Problems: (1) Complete the following neutralization reactions. HNO3(aq) + KOH (aq) _________ + __________ HCl (aq) + Ca(OH)2 (aq) __________ + ___________ (2) How many moles of Ca(OH)2 will it take to neutralize 0.5 moles of HCl? 3) How many moles of HNO3 will it take to neutralize 3.0 moles of KOH? −1 +2 CaCl2 H2O 2 2 1 mole Ca(OH)2 0.5 moles HCl 0.25 moles of Ca(OH)2 x = 2 moles HCl 1 mole HNO3 3.0 moles KOH 3.0 moles of HNO3 x = 1 mole KOH

23. Determining the Concentration of an Acid (or Base) by Titration (Macid)x(Vacid) = (Mbase)x(Vbase) Practice Problems: • A 25 mL solution of HNO3 is neutralized by 18 mL of 1.0 M NaOH standard solution using phenolphthalein as an indicator. What is the concentration of the HNO3 solution? (2) How many mL of 2.0 M KOH will it take to neutralize 55 mL of a 0.76 M HCl standard solution? ( ) x ( ) = ( ) x ( ) Macid 25 mL 1.0 M 18 mL Macid = 0.72 Molar ( ) x ( ) = ( ) x ( ) 0.76 M 55 mL 2.0 M Vbase Vbase = 20.9 mL