Topic: BASES

Do Now:

Topic: BASES

Do Now:

IDENTIFY a Base Covalent Formulas

metal + OH (exception:NH3 it’s a base too)

Table L

CH3OH is NOT a base. WHY?

Properties of Bases

1. Bitter taste2. Slippery or soapy feeling 3. Electrolytes

– NaOH Na+(aq) + OH-

(aq)

4. React with acids to produce water and salt

5. Bases turn litmus blue

Arrhenius Base

• substance that contains hydroxide group & ionizes to produce OH-1 ions in aqueous solution

NaOH(s) Na+1(aq) + OH-1(aq)

THERE IS A LIMITATION TO THIS MODEL…

– NH3 is a base but it doesn’t contain OH-1 but it produces OH-1

:NH3 + H2O NH4+1 + OH-1

Bronsted-Lowry Base• Base = proton acceptor

OH-1 is base

• Not restricted to aqueous solution

NH3 + H2O NH4+1 + OH-1

NH3 is a base!

Water is amphoteric!Amphoteric = Substance that acts as

both acid & base

Naming Bases

• Name the metal + hydroxide

NaOH = ?

Ca(OH)2 = ?

Mg(OH)2 = ?

Sodium hydroxide

Calcium hydroxide

Magnesium hydroxide

Not all bases are created equal• Strong bases 100% dissociate

• Group 1 and Group 2 metals + OH are considered Strong bases– NaOH Na+(aq) + OH-(aq)

• Weak bases– NH3

REVIEW

• Acids: start with H or end with COOH– Produces H+ ions– Proton Donor

• Bases: metal + OH– Produces OH- ions– Proton Acceptor