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Acid and Base Reactions
Shireen Rudina
ingegneria biologica
Equipe de dibattito
Arrhenius Theory
• In water, acids dissociate to form H+ and bases dissociate to form OH-
HCl + H2O H3O++ Cl-
Concept Q: Which of these options are only acids?
1. HCl, NH3, HI
2. H2CO3, NaOH, HBr
3. H2CO3, NH4+, HCl
4. HI, KOH, HBr
Arrhenius Strong/Weak Acids
• Strong acid– Dissociates completely
• Weak acids- everything else
CH3COOH (aceto)
NH4+
HClHNO3
H2SO4
HBrHIHClO4
Arrhenius Strong/Weak Bases
• Strong bases:LiOHNaOHKOHRbOHCsOHBa(OH)2
Ca(OH)2
Sr(OH)2
• Weak bases: everything else
In teams: Calculate the pH of a 0.05 M HBr solution
1. Is HBr a strong acid? How much does it dissociate?
2. What is [H+]?
In teams: A 0.128 M solution of uric acid (HC5H3N4O3) has a pH of 2.39. Calculate the Ka of uric acid.
1. What is the equation for Ka?
2. What variables do we have?
• http://www.youtube.com/watch?v=YqEK5ECcsDo
• http://www.youtube.com/watch?v=vyOnGA0cmp0
• http://www.elmhurst.edu/~chm/vchembook/183neutral.html
In teams: You have an unknown acid. When you put 1 M in water, you see a pH that corresponds to a specific dissociation
percentage.
• Find the Ka for the acid that dissociates:– Team 1: 1%– Team 2: 2%– Team 3: 0.1%
• What acid do you have?
Arrhenius Acid/Base Reaction
Acid + Base = Salt + WaterHBr + NaOH NaBr + H2O
Neutralization
Phenolphthalein:Purple if pH > 7Colorless if pH<7
A Neutralization Experiment
CO2 + H2O --> H2CO3
Ca(OH)2 + H2CO3 --> CaCO3 + 2 HOH
What is the result of a neutralization reaction: NaOH + H2CO3?
1. NaH2 + H2O
2. NaH2 + H2O + CO3
3. NaHCO3 + H2O
4. NaCO3 + H2O
Bronsted-Lowry Acid/Base Reaction
Conjugate acids and bases