Acid and Bases
Physical Properties
Acid
Taste sour
Citric Acid and Ascorbic:
lemons
Carbonic and
Phosphoric:
carbonated
beverages
Acetic Acid: vinegar
Conduct electricity
Base
Taste bitter
Feel slippery: wet soap
Conduct electricity
Chemical Properties
•
•
•
•
Reactions
Litmus paper
Red = Acidic
Blue = Basic
• Reactions
• Metals and Metal
Carbonates
• Produce H2 or CO2
• Geologists identify
limestone with
hydrochloric acid
Videos
Links on DHS Chemistry blog
Ions
Hydrogen Ion H+
Sometimes H3O+
Hydroxide OH-
Goes back and forth
Hydrogen Bond
Notice
Exponent on 10
Is opposite of
pH
pH = - log [H+]
Think in terms
of the base
pOH
[OH-]
14
1 x 10-14
pOH = -log [OH-]
pH + pOH = 14
7
1 x 10-7
0
1 x 100
Water gains H+
Water loses H+
Neutralization
Base + Acid  Salt + Water
HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)
What type of compounds are each?
Acid Neutralizers
Limestone
Calcium carbonate CCaO3
Oceans and Acid Rain
Sometimes antacids can
interfere with medications
Acid Base Reaction then Decomposition
Why do some breads have holes?
HC2H3O2(aq) + NaHCO3aq)  NaC2H3O2(aq) + H2CO3(aq)
H2CO3(aq)  CO2(g) + H2O(l)
Practice
Write the balanced equation for the reaction
between zinc and nitric acid.
Write the balanced equation for the reaction
between magnesium carbonate and
sulfuric acid.
Answers
Zn(s) + 2HNO3(aq)  Zn(NO3)2(aq) + H2(g)
MgCO3(s) + H2SO4(aq)  MgSO4(aq)
+ H2O(l) + CO2(g)
How do you know if you get hydrogen gas or carbon dioxide gas?
Practice
Identify the base in the reaction.
H2O(l) + CH3NH2(aq)  OH-(aq) +CH3NH3+(aq)
• The base is CH3NH2(aq)
• The reactants have an acid and a base
• The products have conjugate pairs – match
up (think Alg 2)
• There is an OH- ion in the products which is
the conjugate (or pair) base
• What did the OH- start as? This is the
acid (opposite of base)
• So, the other compound must be the base.
Practice
Is the solution in which [H+] = 1.0 x 10-5M
acidic, basic or neutral?
Is the solution in which [OH-] = 1.0 x 10-11M
acidic, basic or neutral?
Answers
Is it H+ or OH-?
•
H+ so low pH is more acidic, pH = 5, <7
so slightly acidic
• OH- so low pOH is basic, pOH = 11, >7
so strong acidic
Or, think pH = 14 – pOH so pH = 3, strong
acid
Practice – Neutralization
Write the formula equation for the reactions
between hydrioric acid and beryllium
hydroxide.
Write the formula equation for the reactions
between perchloric acid and lithium
hydroxide.
hydrioric acid and beryllium hydroxide
Hyrd = hydrogen =H
ioric = iodine = I
Covalent bonding, share 1 eBeryllium = Be is group 2 so 2+
Hydroxide = OH- is 1- so need 2
Ionic bonding, metal and ion
HI
Be(OH)2
perchloric acid and lithium hydroxide
Chloric = Chlorine and Oxygen and
acid so need Cl and O and H
HCIO4
(need a list of common acids)
Lithium = Li is group 1 so 1+
hydroxide = OH- so need 1
Ionic bonding, metal and ion
LiOH
Answers
2HI(aq) + Be(OH)2(aq)  BeI(aq) + 2H2O(l)
Think how many water? So balance the H
HCIO4(aq) + LiOH(aq)  LiCIO4(aq) +
H2O(l)
Keep the ClO4 as a unit even if it does not have ( )