Acid/Base Chemistry

Strong Acids & Bases Dissociate completely in water Also known as strong electrolytes Electrolytes conduct electricity in aqueous solutions The more ions dissociated…the more electricity conducted

Properties of Acids & Bases Produce H+ ions when dissolved in water (H3O+ = hydronium ) Produce OH- ions when dissolved in water

Properties of Acids & Bases Taste tart or sour Taste Bitter

Properties of Acids & Bases Feel Slippery Corrosive to body tissue

Properties of Acids & Bases Turn blue litmus red Turn red litmus blue

Properties of Acids & Bases Electrolytes

Arrhenius Acids & Bases Arrhenius proposed that in an aqueous solution a strong electrolyte exists only in the form of ions, whereas a weak electrolyte exists in part as ions and partly as molecules

Arrhenius Acids & Bases Arrhenius Base – gives off OH-1 in aqueous solution Example: KOH --- K+1 + OH-1 H2O

Arrhenius Acids & Bases Arrhenius Acid - gives off H+1 in aqueous solution Example: HNO3 -- H+1 + NO3-1 H2O

Strong acid + Strong Base Example: HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l) Products = water and a salt

Flaw in Theory This theory suggests that all bases have OH- This does not explain how substances like NH3 are bases

Bronsted-Lowry Acids & Bases Another definition of what an acid and base are Bronsted Acid – Proton (H+1) donor Bronsted Base – Proton (H+1) acceptor

NH3 + H2O NH4+ + OH- Base Acid In the reverse reaction, the OH – would be the base and the NH4 would be the acid

Bronsted-Lowry Acids & Bases Example: HCl + NH3  NH4+1 + Cl-1 Which is the acid and which is the base? ACID BASE

Conjugate Acids & Bases Conjugate Base – what remains after a Bronsted-Lowry acid has given up a proton (AN ACID HAS A CONJUGATE BASE)

Conjugate Acids & Bases Conjugate Acid – what remains after a Bronsted-Lowry base has accepted a proton (A BASE HAS A CONJUGATE ACID)

Conjugate Acids & Bases Let’s Look at a few examples: HCl + NH3 NH4+1 + Cl-1 Conjugate Base Base Conjugate Acid Acid

Conjugate Acids & Bases H2SO4 + H2O  H3O+1 + HSO4-1 Acid Base Conjugate Acid Conjugate Base

Conjugate Acids & Bases HF + H2O  F-1 + H3O+1 Acid Base Conjugate Base Conjugate Acid

Amphoteric Substances that can be an acid or a base They can gain or lose H+1 H2O

Try This: Of the following one is acidic, one is basic and one is amphoteric HNO2 PO4-3 HCO3-1

Self-Ionization of Water 2 H2O ↔H30+ + OH- This is constantly happening in pure water. Equilibrium concentration expression for water: Kw = [H3O+] [OH-]

Self-Ionization of Water @ 25 C 2 H2O ↔H30+ + OH- n/a [1x10-7] [1x10-7] Ion product of Water : Kw = [ products] = 1x 10-14 [reactants]

pH Low pH = very acidic High pH = very basic (alkaline) 7 = Neutral

Calculating pH pH = -log [H30 +1 ] To calculate, use: [H30 +1 ] = hydronium ion concentration

Find the pH of a solution whose [H30 +1 ] is 4.0 x 10-6 M.

Find the pH of a solution whose hydronium concentration is 1.0x 10-8 M.

What is the [H30 +1 ] of a solution with a pH of 3.2?

What is the [H30 +1 ] of a solution with a pH of 11?

So what would be the pH of water? If the [H3O+] = 1 X 10 -7 ???

Find the pOH of a solution whose [OH-1] is 2.1 x 10-8 M.

What is the [OH-1] of a solution with a pOH of 9.1?

What is the pH if the pOH is 12.2?

What is the pOH if the [H30 +1 ] is 6.2 x 10-1?

Titrate Strong Acid with a Strong Base What is the pH at each of the following points in the titration of 25.00 mL of 0.100 M HCl with 0.100 M NaOH? a) Before addition of any NaOH (initial pH) b) After addition of 24.00 mL 0.100 M NaOH c) After the addition of 25.00 mL 0.100 M NaOH d) After the addition of 26.00 mL 0.100 M NaOH

Review Links http://www.sciencegeek.net/Chemistry/taters/Unit6AcidsBases.htm http://www.sciencegeek.net/Activities/phcalcs2.html http://www.sciencegeek.net/Activities/phcalcs.html http://www.sciencegeek.net/Chemistry/Review/AcidsBases/ http://www.sciencegeek.net/Chemistry/Review/Solutions/ http://www.sciencegeek.net/Chemistry/Review/Molarity/