GPS 15 Acids, Bases and Salts  I can explain the difference between the Arrhenius theory of an acids and bases and the Bronsted-Lowry theory of acids and bases.  I can identify common examples of acids and bases. VinegarAmmonia

GPS 15 Acids, Bases and Salts  I can explain the differences between a strong, weak and non-electrolyte.  I can calculate pH and relate the hydronium ion concentration to the pH scale.

GPS 15 Acids, Bases and Salts  I can perform titrations.  I can explain how to choose an indicator for a titration.  I can compare and contrast strong/weak, concentrated/dilute acids.  I can calculate Kw.

GPS 15 Assignments  Read Properties of Acids and Bases on p. 1 of the resource notes and complete the Properties or Acids and Bases Graphical Organizer. Turn in assignment.  Read Electrolytes on p. 2 of the resource notes and complete the Electrolyte Inquiry. Turn in assignment.  Complete the Using a Buret Activity. Turn in assignment.

Acids, Bases, and Salts

Some Properties of Acids  Produce H + (as H 3 O + ) ions in water (the hydronium ion is a hydrogen ion attached to a water molecule)  Taste sour  Corrode metals  Electrolytes  React with bases to form a salt and water  pH is less than 7  Turns blue litmus paper to red “Blue to Red A-CID”

Some Properties of Bases  Produce OH - ions in water  Taste bitter, chalky  Are electrolytes  Feel soapy, slippery  React with acids to form salts and water  pH greater than 7  Turns red litmus paper to blue “Basic Blue”

Other Properties of Acids and Bases  Metals in Acids  Zinc in HCl demo  What is produced?  Taste  Acids taste __________  Bases taste _________

Acid/Base Theory TheoryAcid DefinitionBase Definition Arrhenius Substance that releases a H + or H 3 O + ion in water Substance that releases an OH - ion in water Bronsted- Lowry Substance that donates a proton (H + ) Substance that accepts a proton (H + ) H 3 O + is a hydronium ion. It forms from a H+ ion bonding with a water molecule.

Classifying acids, bases, salts   Acids   donates a proton (H + )   releases H + in water   Bases   accepts a proton (H + )   releases OH - in water   Salts   dissolve in water; bound ionically   Is not classified as an acid or base using the definitions above

Acids, Bases and Salts Classify each of the following compounds as acid, base or salt: HCl NaOH NaCl H 2 SO 4 Ca(OH) 2 H 2 O

Bases without OH - Example: HCl (aq) + H 2 O (l) → H 3 O + (aq) + Cl - (aq) Is HCl an acid or a base? Why?Is HCl an acid or a base? Why? Is H 2 O an acid or a base? Why?Is H 2 O an acid or a base? Why?

Bases without OH - Example: H 2 O (l) + NH 3(l) → NH 4 + (aq) + OH - (aq) Is H 2 O an acid or a base? Why?Is H 2 O an acid or a base? Why? Is NH 3 an acid or a base? Why?Is NH 3 an acid or a base? Why?

Acid Nomenclature Acids that do NOT contain oxygen: hydro__________ic acid Examples  HBrhydrobromic acid H 2 S HI HF

Acid Nomenclature Acids that contain oxygen: Example: Ends in –ate, change to –icper- Ends in –ate, change to –icper- : one more oxygen Ends in –ite, change to –oushypo- Ends in –ite, change to –oushypo- : one less oxygen AcidAnionName HClO 4 rate perchlorate perchloric acid HClO 3 chlorate chloric acid HClO 2 chlorite chlorous acid HClO ite hypochlorite hypochlorous acid

Acid Nomenclature Practice: Name the acids. HCl H 2 S HNO 3 HBr H 2 CO 4 H 2 SO 3

Base Nomenclature  Most bases consists of a metal bonded to a hydroxide ion.  Name as ionic compound.  Example: NaOH

Base Nomenclature  Practice: Name the bases. Name the bases.  Ca(OH) 2  Fe(OH) 3  NH 4 OH  LiOH  Co(OH) 2  Al(OH) 3

Electrolytes  Acids, Bases, and Salts dissociate in water (break apart into ions)  Ions conduct electricity  Substances can be:  strong electrolytes  weak electrolytes  nonelectrolytes Hydration Simulation

Electrolytes Type of ElectrolyteSolubilityIonsConductor of electricity? Strong electrolyteDissolves in water Completely breaks into ions Very good conductor Weak electrolyteDissolves in water Partially breaks into ions Poor conductor NonelectrolyteDissolves in water ions No ionsNo conduction

Determining Acidity   Acidity   measured using the pH scale

Determining Acidity   pH   measure of the H + or H 3 O + ions in solution pH = -log [H + ] orpH = -log [H 3 O + ]   pOH   measure of the OH - ions in solution pOH = -log [OH - ]   pH + pOH = 14 [ ] means concentration of Recall: [ ] means concentration of

Concentration  Concentration also called molarity  Units are moles per liter, but symbolized as M  Example: 4.0 moles per liter = 4.0 M (said 4.0 molar) 4.0 moles per liter = 4.0 M (said 4.0 molar)  4.0M HCl solution has a [H+] = 4.0  1.1 x M NaOH solution has a [OH-] of 1.1 x 10 -2

Calculating pH and pOH Example Find the pH and the pOH for a 3.0 x M solution of HCl? pH= -log(3.0 x )= 3.52 pOH= 14 - pH= = 10.48

Calculating pH and pOH Example Find the pH and the pOH for the following: A 1.9 x M solution of NaOH?

Calculating pH and pOH Practice: Find the pH and the pOH for the following: 9) 5.4 x M solution of KOH? 10) 1.0 M solution of HBr? pOH = 14 pOH = 1.3 pH = 0 pH = 12.7

Indicators Indicator pH range for color change Methyl violet Bromphenol blue Methyl red 5-6 Litmus6-7.5 Phenolphthal ein 8-10 Alizarin yellow Acid or base that undergoes dissociation at a know pH range Acid and base form have different colors Chosen based on pH range and on how dramatic the color change is.

Indicators Indicator pH range for color change Methyl violet Bromphenol blue Methyl red 5-6 Litmus6-7.5 Phenolphthalein8-10 Alizarin yellow Example: What indicator could be used if the color change will occur at a pH of 4? Phenolphthalein

Indicators Indicator pH range for color change Methyl violet Bromphenol blue Methyl red 5-6 Litmus6-7.5 Phenolphthalein8-10 Alizarin yellow Practice: What would be the best indicator for a color change at the pH of 9? Bromphenol blue

Natural Indicators Red Cabbage

Natural Indicators Acidic SoilAlkaline (Basic) Soil or Neutral Soil Hydrangea

Neutralization Reactions General equation: Acid + Base → Salt + Water Example: HCl + NaOH → HCl + OH - → Cl - + H 2 O NaCl + H 2 O BaseAcidConjugate Acid Conjugate Base

Neutralization Reactions Practice: 12) List which is the acid, the base, the conjugate acid, and the conjugate base. HNO 3 + OH - → H 2 O + NO 3 -

Titrations   Titration   The reaction between an acid and a base used to find the concentration of the unknown acid or base.   Neutralization reaction occurs   An indicator is used to find the “end point”   Equivalence point (i.e. the “end point”)   when the number of moles of the acid equals the number of moles of the base

Titrations Use the equation below when calculating the unknown concentration of the acid or the base M 1 V 1 = M 2 V 2 M 1 = molarity (concentration) of acid V 1 = volume of acid used during titration in liters M 2 = molarity (concentration) of base V 2 = volume of base used during titration in liters

Titrations Example: It takes mL of NaOH to reach the end point with mL of M HCl. What is the concentration (molarity) of NaOH?

Titrations Practice: 12) It takes mL of HCl to reach the end point with mL of 1.2 M NaOH. What is the concentration (molarity) of HCl?