Acids & Bases

Acid/Base Theory Acids and bases are solutions which can be described differently by multiple theories. So far, we have treated everything that utilizes “H” as a cation = ___________________ H3PO4 “OH” as an anion = _________________ NaOH

Arrhenius Theory The theory that anything capable of producing ________ ions are acids and those producing ________ anions are bases is Arrhenius’ Theory of acids/bases. Based on the notion that these substances _______________ in solution into their ions. H2SO4 H20

Acid or Base? HNO3 KOH Ca(OH)2 HBr HC2H3O2 Al(OH)3

Bronstad Lowry Acids/Bases More general description of acids and bases, incorporates all Arrhenius acid/bases Acids = ___________________________________ Bases = ___________________________________ Example: NH3 (aq) + H2O (l) Would solutions of NH3 be acidic or basic?

Conjugate Acids/Bases NH3 (aq) + H2O (l) NH4+ (aq) + OH-(aq) ____________________: The compound remaining after H+ acceptance by a base. NH3 NH4+ Base Conjugate Acid ____________________: The compound remaining after H+ donation by an acid. H2O OH- Acid Conjugate Base

Lewis Acid/Bases Describes Acid/Bases based upon electron donation. Lewis Acid: A substance that can _____________ a pair of electrons to form a covalent bond. Lewis Base: A substance that can _____________ a pair of electrons to form a covalent bond. H + + OH - H2O

Strength of Acids/Bases For this class, we will mostly discuss Arrhenius acid/bases (H+ cation/OH- anion) The strength of these solutions is determined by the ___________________ of H+ or OH- ions in the solution. Dependent upon… 1) 2)

Concentration of solute Just like calculating the molarity of non acid/base solutions. M = Example: What is the concentration of a H2SO4 solution if 13.2 g of solute are dissolved in 100mL of di-water?

Calculating [H+ ] & [OH-] However, we cannot assume the molarity (concentration) of H+ /OH- ions is the same as the molarity of the solution for 2 reasons: Not all

Dissociation Complete dissociation: all solute dissociates into ions, meaning the concentration of ions can be calculated with the __________ _____________. HCl H+ + Cl- 1 mol HCl produces 1 mol H+ So a 0.2M HCl solution would have a H+ concentration of ______________

Complete Dissociation Few acids/bases completely dissociate If they do, they are termed “____________ _______________” because they produce high concentrations of their ions upon dissociation. Strong Acids (7): Strong Bases (8):

Calculating ion donation Not all acids/bases donate 1 H+ or OH- into solution when they dissociate! How many ions would the following acids/bases donate if they completely dissociate? HBr Ca(OH)2 H2SO4

[H+] Example Using the previous H2SO4 example (13.2 g of solute are dissolved in 100mL of di-water), calculate the [H3O+] of the solution.

Partial Dissociation Weak acids/bases do not completely dissociate in water. They are called weak, because a ____________ concentration of H+ or OH- ions results. Example: Only about 1% of Phosphoric Acid (H3PO4) dissociates into H+ + H2PO4.

Dissociation of Strong & Weak Acids/bases In other words, you would need to know what _____________________ of an acidic/basic compound is likely to donate its ions into solution in order to calculate the [H+ ] & [OH-]. For this class, we will be working with strong acids/bases. So complete _______________________ (ion donation) can be assumed.

Potential of Hydrogen pH = _______________________________ pH is an expression of the concentration of _____________ in solution. Since H+ readily reacts with water to form H3O+, we calculate… pH = −log [H3O+] [H3O+] = 10-pH

pH & POH Just as pH is an expression of the concentration of H+ ions in solution, pOH expresses the concentration of OH- ions in solution… pOH = −log [OH-] [OH-] = 10-pOH pH & pOH always add up to 14 and thus are related through the equation: pH + pOH = 14

pH Scale pH < 7 pH = 7 pH > 7 High [H3O+] Low [H3O+] [H3O+] = ~1x10-7

Acid/Base Reactions Also known as ____________________ reactions, because the pH of the final solution becomes neutralized towards pH=7 Either [H3O+] or [OH-] is __________________by forming more neutral products. Acid + Base Salt + Water

2) Acid + Carbonate Salt + H2O + CO2 Acid/base reactions 2 Types you will need to know… 1) Acid + Base Salt + H2O 2) Acid + Carbonate Salt + H2O + CO2

Acid/base reaction #1 Example: Hydrochloric acid reacts with sodium hydroxide.

Acid/Base Reaction #2 Example: Potassium carbonate reacts with sulfuric acid.