Examples of Common Acids:• citrus aspirin Pepsi, _________ juices, ___________, stomach acid, battery vinegar DNA acid, _____________, ______
Acid Vocabulary• monoprotic acid- contains ____ [H+] ion in its formula 1 HCl HNO3 Examples: _______ , ________• 2 diprotic acid- contains _____ [H+] ions in its formula H2SO4 H2CO3 Examples: _______ , ________• 3 triprotic acid- contains _____ [H+] ions in its formula H3PO4 H3BO3 Examples: _______ , ________• dissociate many strong acid - readily ___________ to produce ______ [H+] ions in water HCl Examples: _________, HNO , _______H2SO4 3 small• weak acid - produces a __________ amount of [H+] ions when in water H2CO3 lemon juice Examples: HC H O (vinegar) , _________, _________ 2 3 2
Indicators• An indicator is a chemical that will change ___________ when colors placed in an acidic, basic or neutral environment. Indicator Colors For Acids• red litmus paper = _______• clear phenolphthalein = ___________• red cabbage juice (universal indicator) = ________ red• red methyl orange = _______
pH Paper : Indicator ColorsNeutral Acidic Basic
Properties of BasesWhat make something a base?Base Properties: (…the opposite of acid properties) bitter banana(1) tastes ________ -- ___________ peel , parsley, dark chocolate slippery soap(2) feels _____________ -- ________ OH−(3) contains [ _____ ] ions acceptor(4) proton ([H+]) ______________-- Brønsted-Lowry Theory Example: NH + H O ______ NH4+ + _______ OH− 3 2
Indicator Colors for Bases• litmus paper = _______ blue• yellow methyl orange = ____________• blue red cabbage juice (universal indicator) =________• phenolphthalein = ______ pinkphenolphthalein Acid Base
Common Bases• ammonia Examples of Common Bases: milk of magnesia, ___________, drain cleaner, soap, blood, ____________ tablets, ___________ antacid baking soda ________.
Strong Bases vs. Weak Bases• strong base- readily __________ to produce ______ [OH−] ions in dissociate many water Examples: KOH NaOH , ________• small weak base- produces a __________ amount of [OH−] ions when in water NH3 Examples: _____ (ammonia); Mg(OH) (milk of magnesia) 2 Other Vocabulary• Alkaline _______________- another term for basic solutions Amphoteric• _______________- a substance that can act as both an acid and a base H2O HCO3− Examples: ___________ , ____________
Conjugate Acid-Base Pairs• Conjugate ______- substance formed when a _______ gains a Acid base [H+] ion.• Base acid Conjugate ______- substance formed when an ______ loses a [H+] ion.• Practice Problems: Label the acid & base on the left side of the reaction and the conjugate acid & conjugate base on the right side. a) HCl + H2O H3O+ + Cl− acid ______ base C.A. C.B. ______ ______ ______ b) NH3 + H2O NH4+ + OH− base _____ acid C.A. C.B. ______ ______ ______
Self-Ionization of Water• Pure water is _____________. It can ionize itself to form OH− and neutral H3O+ ions in __________ amounts. small H2O + H2O H3O+ + OH− H+ (or H2O _______ + _______ OH− ) green• The universal indicator color is ___________ in neutral solutions. self-ionization of water
Measuring the Amount of H+ and OH− Ions in a Solution• _____ Scale- measures the _____________ of [H+] ions in a solution pH concentration• pOH OH− _____ 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: below Acids have a pH _________7.0 above Bases have a pH _________7.0 = Neutral pH ___7.0
Practice Problems:1) a) Calculate the pH of a 0.001 M HCl solution [H+] = 0.001 M So…pH = − (log 0.001 M) pH = 3 b) What is the pOH of this solution? pH + pOH = 14 So…14 − 3 = pOH pOH = 11 c) What is the concentration of [OH−] ions in the solution? [OH−] = 10−pOH [OH−] = 10−11 Molar or 1 x 10−11 M2) a) Calculate the pOH of a NaOH solution that has a pH of 8.50 pH + pOH = 14 So…14 − 8.5 = pOH pOH = 5.5 b) What is the [OH−] of this solution? [OH−] = 10−pOH [OH−] = 10−5.5 Molar or 3.16 x 10−6 M c) What is the concentration of [H+] ions in the solution? [H+] = 10−pH [H+] = 10−8.5 Molar or 3.16 x 10−9 M
Ch. 21 Notes -- Neutralization Neutralization Reactions• salt When an acid and base are mixed, the reaction produces _______ water and ___________.• If the initial concentrations and volumes of the reactants are equal, neutral the products will be ____________... (pH= 7.0)• double All neutralization reactions are ___________ replacement reactions. HX + M(OH) ______ + ______ MX H2O (“Salt”)
Titration• Mixing an acid with a base to determine a __________________ concentration is called “titration.”• An ____________ is used to indicator determine when neutralization has occurred.• Standard ________________ Solution - the solution of known concentration• End Point ______ _________ - the point of neutralization when titrating• end At the ______ point, the moles of [H+] ions = moles of [OH−] ions.
Practice Problems:(1) Complete the following neutralization reactions. HNO3 (aq) + KNO3 H2O KOH (aq) _________ + __________ 2 HCl CaCl2 +2 −1 2H2O (aq) + Ca(OH)2 (aq) __________ + ___________(2) How many moles of Ca(OH)2 will it take to neutralize 0.5 moles of HCl? 0.5 moles HCl x 1 mole Ca(OH)2 = 0.25 moles of Ca(OH)2 2 moles HCl3) How many moles of HNO3 will it take to neutralize 3.0 moles of KOH? 3.0 moles KOH x 1 mole HNO3 = 3.0 moles of HNO3 1 mole KOH
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? ( Macid ) x ( 25 mL ) = ( 1.0 M ) x (18 mL ) Macid = 0.72 Molar(2) How many mL of 2.0 M KOH will it take to neutralize 55 mL of a 0.76 M HCl standard solution? (0.76 M ) x ( 55 mL ) = ( 2.0 M ) x ( Vbase ) Vbase = 20.9 mL
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