View
224
Download
0
Category
Tags:
Preview:
DESCRIPTION
nota kimia
Citation preview
Chemistry
Lecture 10 Acid & Base
M. Adam Adman
Objec=ves:
Proper=es Defini=ons Strong vs. weak acids/bases Titra=ons
Acid & Base
hLp://www.youtube.com/watch?v=DQk7f6DksN8
hLp://www.youtube.com/watch?v=tNvP3-174_M
hLp://www.youtube.com/watch?v=VX6fazASd7w
acids Produce H+ (as H3O+) ions in water (the hydronium ion is a hydrogen ion aLached 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
Base
Produce OH- ions in water Taste biLer, 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
Defini=ons:
Defini=on #1: Arrhenius (tradi=onal)
Acids produce H+ ions (or hydronium ions H3O+)
Bases produce OH- ions
Defini=on #2: Brnsted Lowry
Acids proton donor
Bases proton acceptor
Defini&on #3 Lewis Lewis acid - a substance that accepts an electron pair
Lewis base - a substance that donates an electron pair
Strong vs. Weak
The strength of an acid (or base) is determined by the amount of IONIZATION.
Strong acids
Hydrochloric acid, HCL Nitric acid, HNO3 Sulfuric acid, H2SO4
Weak acids
Weak acids are much less than 100% ionized in water.
Ex: ace=c acid = CH3CO2H
Strong base
Other Ex: KOH Ca(OH)2
} 100% dissociated in water. NaOH (aq) ---> Na+ (aq) + OH- (aq)
Weak base
Less than 100% ionized in water Ex: Ammonia
ACID-BASE REACTIONS Titrations
H2C2O4(aq) + 2 NaOH(aq) ---> acid base Na2C2O4(aq) + 2 H2O(liq)
Carry out this reac=on using a TITRATION. Oxalic acid,
H2C2O4
Setup for =tra=ng an acid with a base
Titra=on
1. Add solu=on from the buret. 2. Reagent (base) reacts with
compound (acid) in solu=on in the flask.
3. Indicator shows when exact stoichiometric reac=on has occurred. (Acid = Base)
This is called NEUTRALIZATION.
Reference:
Raymond Chang. General Chemistry-the essen=al concepts, 5th ed., McGraw-Hill.
Tutorial 10
Please give 1 example: Strong acid Weak acid Strong base Weak base
Recommended