Unit 11 Objectives: Acids & Bases - KRISTINA LESTIK
Unit 11 Objectives: Acids & BasesAcid-Base NomenclatureContent Objectives: I can name ionic compounds containing acids, and bases, using (IUPAC) nomenclature rules. I can write the chemical formulas of acids and bases.Criteria for Success: I can identify an acid as a binary acid or an oxyacid. I can name common binary acids, oxyacids, and bases given their chemical formula. I can write the formula for common binary acids, oxyacids, and bases given their chemical name.EquilibriumContent Objective: I can explain the process of chemical equilibrium as a dynamic, reversible state in which rates of opposing processes areequal.Criteria for Success: I can identify that in many classes of reactions, it is important to consider both the forward and reverse reaction. I can define and interpret the equilibrium constant, K.Arrhenius Acids and BasesContent Objectives: I can define acids and bases according to Arrhenius’s theory. I can distinguish between degrees of dissociation for strong and weak acids and bases.Criteria for Success: I can define acid and base according to Arrhenius’s theory. I can explain the differences between strong and weak acids and bases.Brønsted-Lowry Acids and BasesContent Objective: I can define acids and bases according to Brønsted-Lowry theory.Criteria for Success: I can define a Brønsted-Lowry acid as a proton donor. I can define a Brønsted-Lowry base as a proton acceptor. I can identify Brønsted-Lowry conjugate acid-base pairs in aqueous acid-base reactions.Self-Ionization of Water and K wContent Objective: I can describe the self-ionization of water and describe a solution in terms of concentrations of H and OH .Criteria for Success: I can define the ionization constant of water, K w . I can calculate H and OH concentration using K w .The pH ScaleContent Objective: I can define pH and use the hydrogen or hydroxide ion concentrations to calculate the pH of a solution.Criteria for Success: I can explain and use the pH scale. I can calculate pH or pOH given [H ] or [OH ], and calculate [H ] or [OH ] given pH or pOH.Neutralization Reactions and Acid-Base TitrationsContent Objective: I can understand acid-base reactions and predict products in acid-base reactions that produce water.Criteria for Success: I can define neutralization. I can predict the products in a neutralization reaction. I can explain how to carry out an acid-base titration. I can calculate the concentration of a solution from titration data.
Unit 11 Part 1: Intro to Acids and Bases Lab!Procedure1.If your group starts with the bromothymol blue indicator,a. Place ONE drop of bromothymol blue indicator in 8 different wells. Record the color of thebromothymol blue indicator.b. Add of drop of one of your solutions to one of these wells. Record the color change. Repeat with theremaining solutions.c. When your partner team is ready, pass your solutions and the indicator to them!2. If your group does NOT start with the bromothymol blue indicator,a. Add of drop of one of your solutions to one of these wells. It will look like water, so make sure youknow which solution you put where. Repeat with the remaining solutions.b. When your partner team is ready, pass your solutions to them!c. After acquiring the bromothymol blue indicator, place ONE drop of the indicator into each solutionand record the color.d. Place ONE drop of bromothymol blue indicator in a well by itself. Record the color of the indicator.Data Table 1FormulaColor Change?FormulaUnknown ISolution 3: H 2 SO 4Unknown IISolution 4: Mg(OH) 2Solution 1: KOHSolution 5: LiOHSolution 2: HClSolution 6: HC 2 H 3 O 2Color Change?Analysis1.What is the original color of bromothymol blue indicator?2. Get this information from your teacher:a. Acidic substances turn the bromothymol indicator the color .b. Basic substances turn the bromothymol indicator the color .3. Which compounds were acids? List them here:4. What does the chemical formula of each acid have in common?5. Which compounds were bases? List them here:6. What does the chemical formula of each base have in common?7. Was ‘Unknown I’ an acid or a base? How do you know?8. Was ‘Unknown II’ an acid or a base? How do you know?
Unit 11 Part 2: Acid-Base NomenclatureTypeBinary AcidOxyacid2 elementsMore than 2 elementsHydrogen elementHydrogen polyatomiclook at polyatomic name-ate -icPrefixRootHydro ROOT icRulesHydro-root-ic-ite -ousadd acid at the endAdd acid at the endNaOH sodium hydroxideH 2 SO 3 sulfitehydrochloric acidName toformulaMetal name hydroxidesulfuric acidhydro chlor icExamplesMetal hydroxideH 2 SO 4 sulfateHClTry These:BaseLiOH lithium hydroxidesulfurous acidH 3 N:H 3 PO 4 :KOH:HF:HClO:Cu(OH) 2hydrophosphoric acid:carbonic acidmagnesium hydroxide:hydroiodic acid:bromous acid:lead (III) hydroxide:*Exceptions to acid naming: sulfur and phosphorus-based acids keep three syllables, not just two! (NOT sulfic/phosphic)Tricks to remember oxyacids: “I ate something gross – ic!” And avoid the terrible disease “Ate-IC H) 2H 2 SO 3LiOHH 2 SO 4Pb(OH) 4H 3 PO 3Mg(OH) 2HBrOZn(OH) 2HNO 2potassium hydroxideHClO 4iron (II) hydroxidenitric acidsilver hydroxidecarbonic acidcalcium hydroxidehydrofluoric acidiron (III) hydroxideacetic acidlead (IV) hydroxidephosphoric acidgallium hydroxide
Unit 11 Part 3: Definitions and ConjugatesArrhenius Acids and Bases Defined by what is donatedArrhenius acid: hydrogen ion (H ) ordonorExamples: HCl, H 2 SO 4 , H 2 OArrhenius base: ion (OH–)donorExamples: NaOH, Ca(OH) 2 , H 2 OHCl (aq) H (aq) Cl– (aq) NaOH (aq) Na (aq) OH– (aq)Note: H ions are so reactive they cannot exist in water . Instead, they react with water molecules toproduce complex ions, mainly hydronium ion, H 3 O . Be careful: H and H 3 O are often used interchangeably! (!!!) Because of hydronium, acid dissociation reactions can be written in two, equivalent ways!Shortcut DissociationMore Accurate Dissociation ReactionHBr H Br HClO2 H ClO2 Relative Strength of Acids and Bases: All about the Ionization!Strong Acid or Base ionized in water (completely dissociates)o [H 3 O ] [strong acid]o [OH-] [strong base]Strong electrolytes (conduct electricity in solution) Weak Acid or BaseMuch less than ionized in watero [H 3 O ] [weak acid]o [OH-] [weak base]Weak electrolytesVast majority of acids/bases are weak!
Memorize the following strong acids and bases! Strong acids:o Hydrohalic acids: HCl, HBr, HI (note: HF is NOT a strong acid! The H – F bond is too strong.)o Sulfuric acid: H 2 SO 4o Nitric acid: HNO 3o Perchloric acid: HClO 4 BriCl-SO-NO-ClO (pronounced “Brickle-So-No-Clo; all long “oh” sounds) Strong bases: Group IA and IIA metal hydroxides (i.e. LiOH, NaOH, Ca(OH) 2 , etc) Everything else is weak! ExamplesNameAcid asesdonoracceptorCompound1.Strong orWeak?ConductivityHFDissociation equation:2. H2SO4Dissociation equation:3. Mg(OH)2Dissociation equation:Brønsted-Lowry Acids and Bases Defined by relationship to protonsNotesChemists prefer the Brønsted–Lowry definition, because it Illustrates the ofacid/base reactions as a proton exchange. To examine why, let’s look at how the Bronsted-Lowry base, NH 3(ammonia) reacts with water:NH 3 H 2 O NH 4 OH Note: when a Bronsted-Lowry base reacts with water, is still produced! But it comes from what’sleft of the water molecule after NH 3 removes a proton ( ). You MUST know (i.e. memorize) that NH 3 is a (Brønsted-Lowry) base!
Examples: 1) Identify each of the following as Arrhenius or Brønsted-Lowry acids or bases (mark all that apply).2) In each box that you mark, write the formula for the substance that is Mg(OH)2HCO3NH3NH4 Terms to Know Monoprotic acids: donate one H (ex. HC 2 H 3 O 2 ) Diprotic acids: donate two H ’s (ex. H 2 C 2 O 4 ) Polyprotic acids: donate many H ’s (ex. H 3 PO 4 ) Be careful! Acids only donate ONE proton at a time! Polyprotic bases: accept more than one H ; anions with -2 and -3 charges (ex. PO 4 3-; HPO 4 2-) (or amphiprotic): substances can act as acids or bases (ex. H 2 O, HCO 3 -,and H 2 PO 4 2-)HCl(aq) H 2 O(l) Cl–(aq) H 3 O (aq)o Water as a base, accepting H from HCl.o Water as an acid, donating H to NH 3 .NH 3 (aq) H 2 O(l) NH 4 (aq) OH–(aq)Conjugate Acid-Base Pairs In a Brønsted-–Lowry acid–base reaction, the original base becomes an acid in the reverse reaction, and theoriginal acid becomes a base in the reverse process.o Each reactant and the product it becomes is called a conjugate pair.oConjugate pairs differ by the presence of H ion!HA H 2 Oacidbase A- H 3 O conjugate conjugatebase (CB) acid (CA)Conjugate acid-base pairsandorand By definition, the and are reactants, and theof each are products.
Examples:1. Complete the table below.AcidConjugate BaseBaseConjugate AcidNH4 HClHPO42 H2PO4 HSO4 H2O2. In the following reaction, identify the acid (A), base (B), conjugate acid (CA), and conjugate base (CB).Determine the conjugate pairs.HSO4 H2O H2SO4 OH Practice Makes Perfect!Part 1:Compound1.Al(OH) 3Dissociation equation:2. HC 2 H 3 O 2Dissociation equation:3. H 3 PO 4Dissociation equation:NameAcid orBase?Strong orWeak?Conductivity
Part 2:1) Identify each of the following as Arrhenius or Brønsted-Lowry acids or bases (mark all that apply).2) In each box that you mark, write the formula for HSO 4 H 3 O H 3 PO 4Al(OH) 3NH 3Part 3:1. In the following reactions, identify the acid, base, conjugate acid (CA) and conjugate base (CB).a)HBr(aq) NH 3 (aq) b) HPO 4 2 (aq) H 2 SO 4 (aq)c) CO 3 2 (aq) NH 4 (aq) NH 4 (aq) Br (aq)HSO 4 (aq) H 2 PO 4 (aq)NH 3 (aq) HCO 3 (aq)2. What is the conjugate base of H 2 S?3. What is the conjugate acid of HCO 3 ?4. Which of the following represent a Bronsted-Lowry conjugate acid-base pair?a. H 2 CrO 4 (aq) and CrO 4 2 (aq)c.HCrO 4 (aq) and H 2 O(l)b. HCrO 4 (aq) and CrO 4 2 (aq)d.H 3 O (aq) and OH (aq)
Unit 11 Part 4: Intro to EquilibriumEquilibrium: Another way to measure the strength of acids and bases!Strong Acids and Bases: 100% DissociationWeak Acids and Bases: 1% DissociationAlmost reactants turn into products!Very reactants turn into productsHCl H Cl HF H F start startequilibriumequilibriumWe can write a of the concentration of products to reactants, which gives us a numerical valuethat can be used to compare the relative strength of acids and bases! This ratio is known as the constant, For a generic reaction:𝐾𝐾 [products][reactants]For an acid dissociation:Strong Acid ExampleAt equilibrium:𝐾𝐾𝑎𝑎 [H ][A ][HA]Weak Acid Exampleor[H3 O ][A ][HA]At equilibrium:Notes: Pure and are not included in a K expression K can be negative (it’s a ratio) K has noKexponents of KProductsType of edVery fewWeakNeither[Products] [reactants]Weak(1 x 10x)
Example: Each of the following represents a weak acid placed in water.HA H2O H3O A Rank them in order of increasing Ka (from smallest Ka to largest Ka).Acid 1Acid 2Acid 3But wait! What is “equilibrium”?Dynamic Equilibrium1. Many chemical reactions are , which is indicated by double arrows ( ).2. At equilibrium, both and are present. Forward and backward reactions rates are .o This means that the forward and backward reactions stop! But concentrations of reactants and products are (usually) equal. Instead, the concentrations of the reactants and products are . Rates are , concentrations are .
Example 1: For a given reaction at equilibrium, the concentration of products is found to be significantly higher thanthe reactants. Will the equilibrium constant be less than, equal to, or greater than 1. Justify.Example 2: Complete the table below.EquilibriumReactionconstant, KN2O4 (g) 2 NO2 (g)AB CD AD BCReactant-favored, productfavored, or neither?Strong or weak?Acid or base?K 0.0059K 1.0001Example 3: The following boxes represent reactions of A B at equilibrium. For which reaction shown above doesK have the largest value?Practice Makes Perfect!1.Complete the table below.ReactionHClO 4 H 2 O H 3 O ClO 4 HF H 2 O H 3 O F Al(OH) 3 Al3 3 OH Equilibriumconstant, KReactant-favored, productfavored, or neither?Strong or weak?Acid or base?K 2.4 x 109K 2.4 x 10 9K 0.999992. Which of the following is TRUE?a. When the value of K is large, the equilibrium lies on the reactant side of the equilibrium reaction.b. A small value of K means that the equilibrium concentrations of the reactants are small compared tothe equilibrium concentrations of the products.c. When the value of K is small, the equilibrium lies on the product side of the equilibrium reaction.d. A large value of K means that the equilibrium concentrations of products are large compared to theequilibrium concentrations of the reactants.
Consider the following reversible reaction to answer #3 4.A B 3. Which of the following equilibrium systems has the largest value of K?a.b.c.4. Which of the following equilibrium systems has the smallest value of K?b.b.c.5. Which of the following acids shown at equilibrium below will have the smallest K a value?6. When a reaction reaches equilibrium,a. the forward and reverse reaction rates are equal.b. the rate of the forward reaction is zero.c. the rate of the reverse reaction is zero.d. all reaction stops.7. The acid shown below at equilibrium could possible represent which acid, and why?a. HNO 3 , because the equilibrium constant is greater than 1.b. HNO 3 , because the equilibrium constant is less than 1.c. HNO 2 , because the equilibrium constant is greater than 1.d. HNO 2 , because the equilibrium constant is less than 1.
Unit 11 Part 5: Equilibrium with Acids and Bases Brønsted-Lowry acid-base reactions are equilibrium systems: forward and reverse reactions occur. The extent of the reaction depends on the relative of the acids and bases involved,and the value of their equilibrium constants (K a and K b ).o The stronger an acid is: the its K a value the its conjugate base ( K b )o The stronger a base is: the its K b value the its conjugate acid ( K a )Example 1: Consider the following acids and their Ka values.AcidKa1.Conjugate Base?HC2H3O21.8 x 10 5HOCN3.5 x 10 4HF6.8 x 10 4Rank these acids in order of increasing strength:2. Rank the conjugate bases of the acids in order of increasing strength: The favored direction of the reaction is the one in which theacid/base are produced. HCl H2O Cl H3O Ka 1.3 x 106Example 2:a.b.c.d.e.Example 3:Which direction is favored in this reaction?What are the two acids in this reaction? andWhich acid is stronger?What are the two bases in this reaction? andWhich base is stronger?NH4 Br NH3 HBrK 5.6 x 10 5a. Which direction is favored in this reaction?b. Which acid is stronger?c. Which base is stronger?
Practice Makes Perfect!1.K a 3.2 x 109HClO 4(aq) H 2 O (l) H 3 O (aq) ClO 4 (aq)Favored:2.K a 1.76 x 10 5CH 3 COOH (aq) H 2 O (l) H 3 O (aq) CH 3 COO (aq)Favored:Stronger acid:Weaker acid:Stronger acid:Weaker acid:Stronger base:Weaker base:Stronger base:Weaker base:3. The hypochlorite ion, ClO , is a weaker base than the cyanide ion, CN . Which is a stronger acid, HClO or HCN,and why?Using K a ’s to Determine K eq for a Given ReactionYou can compare the K a values of two acids to determine if a given acid/base reaction is reactant or productfavored!Example:HC2H3O2 HCO3 C2H3O2 H2CO3Ka of HC2H3O2 1.8 x 10 5Ka of H2CO3 4.3 x 10 71. What are the two conjugate acid-base pairs in this reaction?2. What are the two acids in this reaction? and3. Which acid is stronger?4. Is the reaction reactant or product favored?5. Is the K value of this reaction less than 1, equal to 1, or greater than 1?Practice Makes Perfect!1. Consider the reaction of an acid in water: HA(aq) H 2 O(l) H 3 O (aq) A (aq)a. If A is a stronger base than H 2 O, is this reaction reactant or product favored at equilibrium?b. If A is a stronger base than H 2 O, is the value of K greater or less than 1?c. If A is a stronger base than H 2 O, is HA a weak acid or a strong acid?
2. In the following reactions, identify the acid, base, conjugate acid (CA) and conjugate base (CB).a)NH 3 (aq) HClO 3b) HBr (aq) HSO 4 (aq)c) CO 3 2 (aq) H 2 PO 4 (aq)ClO 3 (aq) NH 4 (aq)Br (aq) H 2 SO 4 (aq) HCO 3 (aq) 3. What is the conjugate base of HCO 3 ?HPO 4 2 (aq)4. What is the conjugate acid of HSO 4 ?5. The conjugate acid of H 2 PO 4 is , and the conjugate base of H 2 PO 4 is .6. Given the following acid/base reaction: NO 2 NH 4 NH 3 HNO 2K a of NH 4 5.6 x 10 10K a of HNO 2 4.5 x 10 4a. What are the two conjugate acid-base pairs in this reaction?b. What are the two acids in this reaction? andc. Which acid is stronger?d. Is the reaction reactant or product favored?e. Is the K value of this reaction less than 1, equal to 1, or greater than 1?7. All of the following can function as Brønsted-Lowry bases in solution EXCEPT:a. H 2 Oc. NH 4 b. NH 3d. HCO 3 8. The term “K a for bromous acid” refers to what chemical reaction?
Unit 11 Part 6: Self-Ionization of WaterConverting between a Compound and H /OH Simple dimensional analysis can be used to convert between: [acid] and or [base] and .Example 1: Given an aqueous solution of 3.6 x 10 6 M Ba(OH)2, calculate [OH ].Example 2: If a solution has [OH ] 7.2 x 10 3 M, calculate the molarity of Al(OH)3.Example 3: Given an aqueous solution of HClO3, calculate [H ].Self-Ionization of Water: Water dissociates (or ) to produce H 3 O and OH . The equilibrium constant for the self-ionization of water, K w , is .Let’s Algebra!𝑲𝑲𝒘𝒘 [𝑯𝑯 ][𝑶𝑶𝑶𝑶 ] 𝟏𝟏. 𝟎𝟎 𝟏𝟏𝟏𝟏 𝟏𝟏𝟏𝟏(at 25oC)Neutral, Acidic, and Basic Solutions: A solution is then determined to be acidic or basic depending on which ion is ingreater concentration.Acidic: [H ] [OH ]Neutral: [H ] [OH ]Example 1: Given an aqueous solution of 2.7 x 10 4 M LiOH:a. Calculate [OH ]:b. Calculate [H ]:c. Is the solution acidic, basic, or neutral?Basic: [H ] [OH ]
Example 2: An aqueous solution of KOH has an [H ] concentration of 5.1 x 10 11 M.a. Calculate [OH ]:b. What is the molarity of KOH?c. Is the solution acidic, basic, or neutral? We can also do these calculations with polyprotic acids and bases, but first we need to know how to convertbetween the concentration of a polyprotic species and the number of or ions produced!Example 3: Given a 1.2 molar [H ] solution, what is the concentration of Ca(OH)2 that produced it?Practice Makes Perfect!1. An aqueous solution of Al(OH) 3 is 9.1 x 10 9 molar. Calculate [H ] in solution.2. A 6.5 x 10 4 M solution of HNO 3 has been prepared for a laboratory experiment. Calculate the hydroxide ionconcentration.3. An aqueous solution of Ba(OH) 2 has a [H ] concentration of 4.1 x 10 11 M. What is the molarity of the Ba(OH) 2solution?
Unit 11 Part 7: The pH ScalepH and pOH scale: Another way to express if a solution is acid or basic is to use
Unit 11 Objectives: Acids & Bases Acid-Base Nomenclature Content Objectives: I can name ionic compounds containing acids, and bases, using (IUPAC) nomenclature rules. I can write the chemical formulas of acids and bases. Criteria for Success: I can identify an acid as a binary acid or an oxyacid. I can name common binary acids, oxyacids, and bases given their chemical formula.
2. Describe the common properties of acids and bases 3. Identify acids and bases using indicators, pH papers 4. Name some common lab acids and bases, acids at and bases at home 5. Describe reactions of acids with metals, bases and carbonates 6. Describe the application of acids, bases and p
_7. Which statement describes an alternate theory of acids and bases? (1) Acids and bases are both H acceptors. (2) Acids and bases are both H donors. (3) Acids are H acceptors, and bases are H donors. (4) Acids are H donors, and bases are H acceptors. _8. Which substance is the
Properties of Acids and Bases Return to the Table of contents Slide 5 / 208 What is an Acid? Acids release hydrogen ions into solutions Acids neutralize bases in a neutralization reaction. Acids corrode active metals. Acids turn blue litmus to red. Acids taste sour. Properties of Acids Slide 6 / 208 Properties
Unit 14 – Acids & Bases 1 Worksheets - Honors BRONSTED - LOWRY ACIDS & BASES WORKSHEET According to Bronsted-Lowry theory, an acid is a proton (H 1) donor, and a base is a proton acceptor. Label the Bronsted-Lowry acids (A), bases (B), conjugate acids (CA), and conjugate bases (CB) in the
Unit 12 Acids and Bases- Funsheets Part A: Name and write the formula for the following acids and bases. 1) Carbonic acid _ . Part E: Using your knowledge of acids and bases, answer the following questions. 1) Fill in the following Venn diagram about properties of acids and bases. You must fill in at least 4 facts in each.
properties of acids and bases. 5. Describe the colors that form in acidic and basic solutions with litmus paper and phenolphthalein. 6. Explain the difference between strong acids or bases and weak acids or bases. 7. Memorize the strong acids and bases. 8. Define the terms polyprotic and amphiprotic. 9. Perform calculations using the following .
Acids, Bases, and pH The hydrohalic acids (HX (aq)), where X represents a halogen) include HF, HCl, HBr, and HI. Only HF is a weak acid. The rest are strong acids. What factors account for this difference? 8.1 Explaining the Properties of Acids and Bases 8.2 The Equilibrium of Weak Acids and Bases 8.3
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