Transcript STAAR Ladder to Success - Grandview Independent School

STAAR Ladder to Success
Rung 10
Arrhenius Definition
Savante Arrhenius, Swedish chemist who by
1890 formulated the first useful theory for
acids.
• Acids contain hydrogen ions
• Bases contain hydroxide ions (OH-)
Bronsted-Lowry Definition
• Acids are proton (H+) donors.
• Bases are proton (H+) acceptors.
• Conjugate acid-base pairs are formed.
Bronsted-Lowry Definition
Pairs identifies the particles formed when H+ ions are donated and accepted
when an acid or a base is dissolved in water.
Base gains H+  conjugate acid formed
Particle that remains  conjugate base
HCl + H2O 
acid
–
Cl
+
+
H3O
base
conjugate base
conjugate acid
pH =
+
-log[H3O ]
pOH =
-log[OH ]
pH + pOH = 14
Strength
• Strong Acid/Base
–100% ionized in water
–many ions produced
–strong electrolyte HCl
HNO3
H2SO4
HBr
HI
HClO4
-
+
NaOH
KOH
Ca(OH)2
Ba(OH)2
Strength
 Weak
Acid/Base
• does not ionize completely
• few ions produced
• weak electrolyte
HF
CH3COOH
H3PO4
H2CO3
HCN
-
+
NH3
Determining Types of Reactions
Neutralization
• Chemical reaction between an acid and a
base.
• Products are a salt (ionic compound) and
water.
ACID + BASE  SALT + WATER
HCl + NaOH  NaCl + H2O
• Salts can be neutral, acidic, or basic.
• Neutralization does not mean pH = 7.
Single Replacement
A + BC  B + AC
• Whether one metal will replace another metal from a compound
is determined by the reactivities of the two metals.
• To help us determine this, an activity series of metals arranges
metals in order of decreasing reactivity.
• A reactive metal will replace any metal listed below it in the
activity series.
Precipitation Reactions
• Double replacement reaction where a
precipitate is formed due to the insolubility of
the compound that is formed.
• Refer to the solubility rules.
Oxidation numbers
• The apparent charge assigned to an atom of an
element
– Metal: positive charge
– Nonmetal: negative charge
• Key points to remember:
– The sum of the oxidation numbers of the elements in
any compound is 0.
– The sum of the oxidation numbers of the elements in
any ion (polyatomic) is equal to the charge on the ion.
Reduction-oxidation reactions (redox)
• Any chemical reaction in which changes in
oxidation numbers occur
• Has two parts:
– Oxidation: one reactant is losing electrons or
increases in oxidation number
• The reactant losing electrons or increasing in oxidation
number is known as the reducing agent
– Reduction: other reactant is gaining electrons or
decreases in oxidation number
• The reactant gaining electrons or decreasing in oxidation
number is known as the oxidizing agent
Using oxidation numbers
• If there are changes in atomic oxidation
numbers in the reaction, meaning loss and
gain of electrons, then the reaction IS redox.
• If there are no changes in atomic oxidation
numbers then the reaction IS NOT redox.