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Honors Chemistry Unit 11 – Acids and Bases. Lesson 3 – Properties of Acids and Bases Do Now: Prepare for Quiz 11-2. Over the years, there have been changes to the way an acid or base was defined. Nevertheless, they exhibit the same properties regardless of definition. Properties of Acids
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Honors ChemistryUnit 11 – Acids and Bases Lesson 3 – Properties of Acids and Bases Do Now: Prepare for Quiz 11-2.
Over the years, there have been changes to the way an acid or base was defined. Nevertheless, they exhibit the same properties regardless of definition. Properties of Acids Colorless in phenolpthalein (titration lab) Orange in methyl orange (another indicator) React with most metals Taste sour (citric acid in lemon juice) Turns litmus paper red (Red = Acid) pH 0-6.99 Properties of Acids and Bases
Properties of Bases Bitter tasting (milk is a weak base) Pink in phenolpthalein Yellow in methyl orange Do not react with metals Turns litmus paper blue (Blue = Base) pH 7.01-14 Feel slippery (like soap!) Properties of Acids and Bases
Properties of Both They both sting wounds & flesh They are both electrolytes Both produce salts in reactions An electrolyte is an ion in solution. NaCl Na+(aq) + Cl-(aq) Any salt dissolved in water is an electrolyte. Electrolytes improve the flow of electricity in a solution, which your nerves need to transmit electrical signals throughout your body. http://www.youtube.com/watch?v=uxieMOdo6IU Properties of Acids and Bases
Arrhenius Acid/Base – 1900 Svante Arrhenius An Arrhenius acid is a compound that increases the amount of H+ in solution. HCl, H2SO4 An Arrhenius base is a compound that increases the amount of OH- in solution. Ba(OH)2, NaOH Acid Definitions
BrØnsted-Lowry Acid/Base – 1923 J. N. BrØnsted and T.M. Lowry A BrØnsted-Lowry acid is a proton (H+) donor HCl, H2SO4, H2O (in some cases) An BrØnsted-Lowry base is a proton acceptor NH3 (can become NH4+), H2O can become H3O+ Acid Definitions
HCl + NH3 NH4+ + Cl- This is an example of a Bronsted-Lowry acid/base reaction. The proton on the acid (HCl) is accepted by the base (NH3) After the HCl loses the proton, Cl- is now considered a base (because it could possibly receive a proton again) – called a conjugate base Same with the NH3 accepting the proton – the NH4+ could give the proton away, making NH4+ a conjugate acid. HCl + NH3 NH4+ + Cl- Acid Base C.A. C.B. Acid/Base Reactions
Water, because it is pH neutral, can act as both an acid and a base. Amphoteric – both an acid and a base H2O + H2O H3O+ + OH- Acid Base C.A. C.B. This happens all the time – the reason water is neutral is because at all times, there are equal amounts of H3O+ and OH- !! Water
Homework 11-3: #11-16 • Tuesday: Begin Titration 2 Lab • Wednesday: Titration 2 Lab • Thursday: pH, pOH, Quiz 11-3 • Friday: Formal Report Work (Mr. Cerami @ GlaxoSmithKline) • Acid/Base Exam – Tuesday, May 10th