Unit 9 - Acids and Bases - Honors

Question 1

Definition of Amphoteric (3)

Answer 1

1. Compound that acts as both a base & acid
2. Can donate & accept a proton
3. Depends if they’re reacting w/ acid or base

Water (H₂O):
Acts as a base: When reacting with a strong acid like HCl, it accepts a proton, forming H₃O⁺.
Acts as an acid: When reacting with a strong base like NH₃, it donates a proton, forming OH⁻.

Hydrogen carbonate (HCO₃⁻):
Acts as a base: When reacting w/ acid HCl, it accepts a proton, forming H₂CO₃ (carbonic acid)
Acts as an acid: When reacting with a base like NaOH, it donates a proton, forming CO₃²⁻ (carbonate ion)

Question 2

Definition of Lewis Acid (2)

Answer 2

1. Acids accept e- pair to form coordinate covalent bond
2. Typically contain incomplete octets/orbitals (e- deficient)
3. Electrophilic (e- loving)

Question 3

Definition of Lewis Base (3)

Answer 3

1. Donates e- pair to form coordinate covalent bond
2. Contains lone pair/unbonded pair of e-
3. Nucleophilic (nucleus loving)

Question 4

Definition of Conjugate Acid (4)

Answer 4

1. Protonated Product
2. Received dissociated proton from parent acid
3. Parent Base gains H+ from Parent Acid
4. Becomes Conjugate Acid
   (H+ is Attatched)

Question 5

Definition of Conjugate Base (4)

Answer 5

1.Negatively Charged Product
2.Remains after p+ dissociated from parent acid
3. Parent acid loses its H⁺ to Parent base
4. Becomes a conjugate base
(H+ is Lost)

Question 6

How can you determine the strength of an acid when finding conjugates?

Answer 6

Stronger Acids (Dissociates More) = Weak Conjugate Base (Less likely to grab H+)
Weaker Acids (Dissociates Less) = Strong Conjugate Base (More likely to grab H+)

Strong acids, like HCl, dissociate completely bc weak H⁺ bonds are readily broken due to electronegative atoms like Cl pulling electrons away, resulting in stable, unreactive conjugate bases like Cl⁻ that remain as nonreactive spectator ions in solution.

1. Strong Acids have Weak Bond of H⁺ & molecule
2. Weak bonds make it easier for the acid to dissociate & release the H⁺
3. HCl bond is weak
4. Cl is very electronegative & holds onto shared e- tightly
5. This pulls them away from H
6. Making it an bond easier to break
7. bc H⁺ is even more “ready” to leave
8. When a strong acid loses H⁺
9. Conjugate base is highly unreactive, discouraging dissociation
10. Cl⁻ doesn’t tend to grab H+ & revert back to HCl b
11. HCl completely dissociates in water, leaves Cl⁻ as a non-reactive spectator ion

Question 7

Definition of Ka (3)

Answer 7

1. Dissociation Constants for Acids
2. Determines the Strength of Acid
3. How well something dissociates until they reach equilibrium

Question 8

Definition of Kb (3)

Answer 8

1. Dissociation Constants for Bases
2. Determines the Strength of Bases
3. How well something dissociates until they reach equilibrium

Question 9

What is the formula for Ka? (4)

Answer 9

1. Same formula as Keq
2. Products/Reactants, Convert Coefficients to Exponents
3. Conjugate Acid x Conjugate Base/Parent Acid
4. Water is NEVER included
5. High Ka = Dissociates well, Strong Acid
6. Low Ka = Dissociates poorly, Weak Acid

Question 10

What is the formula for Kb? (4)

Answer 10

1. Same formula as Keq
2. Products/Reactants, Convert Coefficients to Exponents
3. Conjugate Acid x Conjugate Base/Parent Base
4. Water is NEVER included

Question 11

Definition of ICE Tables

Answer 11

Use ICE Tables for this problem
1. 3x3 Table
2. Column - Initial, Change, Equilibrium
3. Row - Parent, H+, Parent - H+
4. I: Initial Conc. (before the reaction starts)
5. C: Change in Conc. (what’s lost/gained during dissociation)
6. E: Equilibrium Conc. (What’s left after rxn balances)
Ex: [H+] of 0.10M solution of HCNO is 0.0010M (Calculate Ka for HCNO)
1. HCNO = H⁺ + CNO⁻
2. HCNO is Acid, H+ is Proton, CNO is Base
3. HCNO is INITIALLY 0.10M, and H+ and CNO- is 0
4. Subtract H+ Conc. from HCNO Conc. & add to H+ & CNO-
5. 0.0010 M of HCNO dissociates, ending in a loss of 0.0010M of HCNO
6. HCNO at Equilibrium = 0.099
7. H+ at Equilibrium = 0.001
8. CNO- at Equilibrium = 0.001
9. Plug in Values to Ka Equation (Remember, Coefficients = Exponents)

Question 12

Rank Strongest to Weakest Acids (10)

Answer 12

1. HI
2. HBr
3. HCl
4. HNO3 (Nitric Acid)
5. H2SO4 (Sulfuric Acid)
6. HClO4 (Perchloric Acid)
7. HClO3 (Chloric Acid)
8. HF
9. HCOOH
10. CH3COOH

(First 3 are Halides, Next 4 have O, then HF and 2 COOH

Question 13

Rank Strongest to Weakest Bases

Answer 13

1. NaOH (Sodium hydroxide)
2. KOH (Potassium hydroxide)
3. LiOH (Lithium hydroxide)
4. Mg(OH)2 (Magnesium hydroxide)
5. Ca(OH)2 (Calcium hydroxide)
6. Sr(OH)2 (Strontium hydroxide)
7. Ba(OH)2 (Barium hydroxide)
8. CH3NH2 (Methylamine)
9. NH3 (Ammonia)
10. NH4OH (Ammonium hydroxide)

Question 14

What’s a Net Ionic Equation?

Answer 14

1. Predict Products of Rxn (Double Replacement of Anions & Cations)
2. Balance Ionic Equation
3. Dissociate Ions (aq) to Cations & Anions (Insoluble Compounds (s) CANNOT Dissociate)
4. Add Charges & Phases - (aq) for dissociated Ions and (s) for insoluble compounds
5. Cross Out Spectator Ions that Dissociated & didn’t change charge/phase
6. NEVER CROSS OUT SOLID INSOLUBLE COMPOUNDS IN REACTANT
7. Weak Acids/Bases will NOT dissociate and never cross it out!

Question 15

How do Acids & Bases apply to Net Ionic Equations?

Answer 15

Weak Acids & Bases (HF, HCOOH, CH3COOH, NH3, NH4, OH, CH3, NH2)

Question 16

What should you do when given the pH instead of the H+ concentration?

Answer 16

H+ = 10⁻ᵖʰ