acids and bases
TRANSCRIPT
Acids and Bases
http://www.unit5.org/chemistry/AcidBase.html
http://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppt
Properties
electrolytes
turn litmus red
sour taste
react with metals to form H2 gas
slippery feel
turn litmus blue
bitter taste
ChemASAP
vinegar, milk, soda, apples, citrus fruits
ammonia, lye, antacid, baking soda
electrolytes
Acid vs. Base
AcidAcid
pH > 7
bitter taste
does notreact with
metals
pH < 7
sour taste
react withmetals
Alike Different
Related toH+ (proton)
concentration
pH + pOH = 14
Affects pHand
litmus paper
BaseBase
Different
Topic Topic
Common Acids and Bases
Strong Acids (strong electrolytes)
HCl hydrochloric acidHNO3 nitric acidHClO4 perchloric acidH2SO4 sulfuric acid
Weak Acids (weak electrolytes)
CH3COOH acetic acidH2CO3 carbonic
Strong Bases (strong electrolytes)
NaOH sodium hydroxideKOH potassium hydroxideCa(OH)2 calcium hydroxide
Weak Base (weak electrolyte)
NH3 ammonia
Kotz, Purcell, Chemistry & Chemical Reactivity 1991, page 145
Weak Base (weak electrolyte)
NH4OH ammonia
NH3 + H2O NH4OH
Common Acids
Sulfuric Acid H2SO4
Nitric Acid HNO3
Phosphoric Acid H3PO4
Hydrochloric Acid HCl
Acetic Acid CH3COOH
Carbonic Acid H2CO3
Battery acid
Used to make fertilizersand explosives
Food flavoring
Stomach acid
Vinegar
Carbonated water
Common Bases
Sodium hydroxide NaOH lye or caustic soda
Potassium hydroxide KOH lye or caustic potash
Magnesium hydroxide Mg(OH)2 milk of magnesia
Calcium hydroxide Ca(OH) 2 slaked lime
Ammonia water NH3 H2O household ammonia
Name Formula Common Name
.NH4OH
NH41+ + OH1-
ammonium hydroxide
hydroxideion
OH1-
Arrhenius Acid
1+
+ +
hydronium ion
H3O+
1-
chloride ion
Cl-
water
H2O
hydrogen chloride
HCl
(an Arrhenius acid)
Any substance that releases H+ ions as the only positive ion in the aqueous solution.
Arrhenius Bases and Their Properties
According to the definition of Arrhenius a:
BaseBase - "a substance whose water solution yields...
Are NaOH and NH3 considered to be Arrhenius bases?
1) Bases are electrolytes
Dissociation equation for NH3
NH3(g) + H2O(l) NH41+(aq) + OH1-(aq)
Dissociation equation for NaOH
NaOH(s) Na1+(aq) + OH1-(aq)
2) Bases cause indicatorsindicators to turn a characteristic color
3) Bases neutralize acidsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)
YES
4) Water solutions of bases tasted bitter and feel slippery.
hydroxide ions (OH-) as the only negative ions."
Each of the following unbalanced equations represents a reaction between a Arrhenius acid and base. Identify those in each reaction:
H2CO3 + NH4OH → (NH4)2CO3 + H2O KOH + H3PO4 → K3PO4 + H2O HF + NaOH → NaF + H2O Ba(OH)2 + HNO2 → Ba(NO2)2 + H2O
Brønsted-Lowry Acids and Bases
1+
+
hydronium ion
H3O+
1-
chloride ion
Cl-
(base)
H2O
(acid)
HCl
+ -
Acid = any substance that donates a proton.
Base = any substance that accepts a proton.
Brønsted-Lowry Acids and Bases
1+
+
hydronium ion
H3O+
1-
chloride ion
Cl-
(base)
H2O
(acid)
HCl
+ -
Acid = any substance that donates a proton.
Base = any substance that accepts a proton.
Identify the Bronsted-Lowry acid and the Bronsted-Lowry base in each reaction.
NH4+(aq) + CN- (aq) → HCN (aq) + NH3 (aq)
(CH3)3N(aq) + H2O → (CH3)3NH+(aq) + OH-(aq)
HCHO2(aq) + PO43- → CHO2
-(aq) + HPO42-(aq)
HSO4-(aq) + CO3
2- → SO42- (aq) + HCO3
-(aq)
DefinitionsDefinitions
LewisLewis• AcidsAcids are electron pair acceptors.
• BasesBases are electron pair donors.
Lewis base
Lewis acid
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Arrhenius Acids and BasesAcids release hydrogen ions in water.Bases release hydroxide ions in water.
An acid is a substance that produces hydronium ions, H3O+, when dissolved in water.
Lewis DefinitionsA Lewis acid is a substance than can accept (and share) an electron pair.A Lewis base is a substance than can donate (and share) an electron pair.
Lewis Acid
Brønsted-Lowry DefinitionsA Brønsted-Lowry acid is a proton donor; it donates a hydrogen ion, H+.A Brønsted-Lowry base is a proton acceptor; it accepts a hydrogen ion, H+.
Brønsted-Lowry
Arrheniusacids
Acid Definitions
Acid Definitions
Lewis acids
Brønsted-Lowry
Arrheniusacids
The Arrhenius model of acidsand bases was broadened bythe Brønsted-Lowry model.
The Lewis acid-base model isthe most general in scope.
The Lewis definition of an acidincludes any substance thatis an electron pair acceptor;a Lewis base is any substancethat can act as an electron pair donor.
Ralph A. Burns, Fundamentals of Chemistry 1999, page 483
Lewis acids
Brønsted-Lowry
Arrheniusacids
The Arrhenius model of acidsand bases was broadened bythe Brønsted-Lowry model.
The Lewis acid-base model isthe most general in scope.
The Lewis definition of an acidincludes any substance thatis an electron pair acceptor;a Lewis base is any substancethat can act as an electron pair donor.
Ralph A. Burns, Fundamentals of Chemistry 1999, page 483
Acid Definitions