Acids and Bases

Acid Definition: aqueous solution of Hydrogen containing compounds Name the following: HCl H2SO4 H2SO3 H2S Remember: H with an element: hydro_______ic acid H with polyatomic ion ending with –ate: _______ic acid H with polyatomic ion ending with –ite: _______ous acid

Acid Definition: aqueous solution of Hydrogen containing compounds Name the following: HCl hydrochloric acid H2SO4 sulfuric acid H2SO3 sulfurous acid H2S hydrosulfuric acid

Base Definition (for now): Contains the polyatomic ion OH-1 (hydroxide) Name the following bases: NaOH Ca(OH)2 Cu(OH)2 NH4OH Follow ionic naming rules: name metal, name nonmetal, do NOT use prefixes! If the metal is a transition metal, use roman numeral for its charge

Base Definition (for now): Contains the polyatomic ion OH-1 (hydroxide) Name the following bases: NaOH sodium hydroxide Ca(OH)2 calcium hydroxide Cu(OH)2 copper (II) hydroxide NH4OH ammonium hydroxide

Properties of Acids Ionize in water  H3O+1 Corrosive to metals and skin. (React with most metals to form hydrogen gas.) Taste sour (like lemons) Frequently feel "sticky" pH less than 7. Neutralizes bases producing salt and water. Electrolytes.

Properties of Bases Ionize in water  OH- Feel "slippery". Taste bitter (like soap) Electrolytes pH greater than 7. Neutralizes acids producing a salt and water.

Indicators Indicators are added to chemicals to determine the pH. They change colors in different pH’s. You need to memorize the indicators and colors!

Acid Base Indicators Type Acid Neutral Base Red Litmus Red Blue Blue Litmus Phenolphthalein Clear Hot pink Bromothymol Blue Yellow Green

Strength vs. Concentration Concentration: amount of acid or base/amount of water or solution Strength: how well that particular acid or base ionizes (amount of H3O+1 or OH- ) Strong acid/base: an acid/base that ionizes almost completely Weak acid/base: an acid/base that only slightly ionizes

Play Strength vs. conc. Video

Acids and Bases

List of Strong and Weak acids HCl H2SO4 HF HC2H3O2 HBr HClO3 H2S H2SO3 HI HClO4 HNO2 H3PO4 HNO3 Organic acids: end in –COOH, weak acid Ex: vinegar  CH3COOH

List of Strong and Weak Bases Group I and II metals with hydroxides NH3 and any non-group I or II hydroxide

Ionization of water Kw = 1 * 10-14 = [H3O+][OH-] Pure water ionize slightly according to this equation: The product of molar concentrations of the ions is equal to a constant Kw. Formula: Kw = 1 * 10-14 = [H3O+][OH-] [ ] means concentration of (molarity) Important Note: H+ and H3O+ are usually interchangeable (basically they are the same)

Relationships In a neutral solution: In an acidic solution: In a basic solution: Basically this is saying there is more H3O+ in acidic solutions, more OH- in basic solutions. The concentrations of both are the same in neutral solutions

pH and pOH Neutral 0 7 14 Acid Base Neutral 0 7 14 Base Acid pH: measure of [H3O+1] in a solution, measure of “acidity” pOH: measure of [OH-1] in a solution, measure of “basicity” Neutral 0 7 14 Acid Base Neutral 0 7 14 Base Acid

More on ph A change in [H+] by a factor of 10 causes the pH to change by 1. Solution with a pH of 6 has 10x the [H+] as a solution with a pH of 7. What is the [H+] difference between pH of 1 and pH of 4? 4-1= 3  that’s how many zero’s Answer= pH 1 has 1000x more

Important formulas 1 4 2 5 3 6

Play pH/pOH calc. Video

Find the pH of the following: [H3O+] = 1.00 x 10-3M [H3O+] = 6.59 x 10-10M   [H3O+] = 7.01 x 10-6M

Find the [H3O+1] pH = 3   pH = 6.61 pH = 2.52

Find the pH for the following: pOH = 2   pOH = 1.26 pOH = 4.98

Find the pH for the following: [OH-] = 1.00 x 10-11M   [OH-] = 2.64 x 10-13M [OH-] = 3.45 x 10-8M

[OH-] = 1.00 x 10-6M [OH-] = 4.97 x 10-10M [OH-] = 2.93 x 10-2M Find the [H3O+1] [OH-] = 1.00 x 10-6M   [OH-] = 4.97 x 10-10M [OH-] = 2.93 x 10-2M

Find the ph 0.054M HCl   0.178M NaOH

Types of Acids and Bases Theory Acid Definition Base Definition Arrhenius Releases H+1 into solution Releases OH-1 into solution Bronsted-Lowery Proton (H+1) donor Proton (H+1) acceptor

What happens when you mix an Arrhenius acid with an Arrhenius base? Neutralization, producing a salt and water Generic Equation: Salt: Ionic compound formed from the cation of a base and the anion of an acid

Name the salt produced and write the balanced reaction: Sodium hydroxide and hydrochloric acid Calcium hydroxide and sulfuric acid Potassium hydroxide and nitric acid Remember: these are double replacement reactions! You will switch the anions of the reactants. Don’t forget to balance charges when making the products! The subscripts might change! That’s okay! 

Name the salt produced and write the balanced reaction: Sodium hydroxide and hydrochloric acid NaOH + HCl  NaCl + H2O Calcium hydroxide and sulfuric acid Ca(OH)2 + H2SO4  CaSO4 + 2H2O Potassium hydroxide and nitric acid KOH + HNO3  KNO3 + H2O

Review Acids and Bases Watch this video by clicking the title

Quiz Topics Acid/Base Properties Acid/Base Definitions Strong vs. Weak Acids and Bases (memorize them!) Neutralization Reactions pH/pOH Calculations

Definitions Monoprotic acid: only has one ionizable hydrogen ex: HCl, HBr, HC2H3O2, HNO3 Polyprotic acid: more than one ionizable hydrogen ex: H2SO4, H3PO4 Amphoteric: substance that can act as an acid or as a base ex: H2O, NH3

Titrations An acid-base titration is a neutralization reaction that is performed in the lab in order to determine an unknown concentration of acid or base. Remember this: MAVA= MBVB M  molarity (M) V  volume (V)

Titrations Endpoint: When the chosen indicator changes color and you stop the titration. Equivalence point: When the solution is completely neutralized. The reaction is complete. [H+] = [OH-]

Titration terms Indicator: weak acid or base and its conjugate ion; whose color changes in different pH’s Standard solution: solution of known concentration used as the titrant Carolina Biological Video

Play Titration Calculations Video

Titrations 1) If it takes 54mL of 0.1M NaOH to neutralize 125mL of an HCl solution, what is the concentration of the HCl? 2) If it takes 25mL of 0.05M HCl to neutralize 345mL of NaOH solution, what is the concentration of NaOH solution?

Play Titration Curve Video

Titration Curves On the following slide you you will see 3 different curves. The relationships are: Strong Acid titrated with Strong Base Weak Acid titrated with Strong Base Strong Acid titrated with Weak Base Using those graphs compare the pH values of each substance as well as the equivalence points

More Titration Curves Strong acid and weak base curve Strong base and weak acid curve Strong acid and strong base curve