Name: ____________________________________________ Period: __________ Date: __________________
Learning Target:
I can define acids and bases according to Arrhenius’s theory.
I can distinguish between degrees of dissociation for strong and weak acids and bases
Criteria for Success:
I can define acid and base according to Arrhenius’s theory
I can explain the differences between strong and weak acids and bases.
Arrhenius Acids and Bases
A. An Arrhenius _________ is a chemical compound that increases the concentration of ________________ ions (H+1), in
aqueous solution. The hydrogen ions are attracted to the water molecules in an aqueous solution and form
_________________________ ions (H3O+1).
B. An Arrhenius _________ is a chemical compound that increases the concentration of ________________ ions (OH-1),
in aqueous solution.
Strength of Acids and Bases
A. A strong acid is one that ionizes completely in an aqueous solution. __________________ ions and _____________
are formed in solution.
HCl(aq) + H2O(l) → H3O+1(aq) + Cl-1(aq)
1. Strong acids are strong __________________________.
2. Acid strength increases with increasing ________________ and decreasing ____________ energy.
B. A weak acid is one that does not dissociate completely in an aqueous solution. In aqueous solution, both the
dissociation and the reverse reaction occur at the same time. ____________________ ions and _________ are formed
in the forward reaction but in the reverse reaction dissolved acid molecules and water are produced.
+1
-1
HCN(aq) + H2O(l) →
← H3O (aq) + CN (aq)
1. Weak acids are poor _________________________.
C. A strong base is one that dissociates completely in an aqueous solution. __________________ ions and
_____________ are formed in solution.
NaOH(s) + H2O(l) → Na+1(aq) + (OH)-1(aq)
1. Strong bases are strong __________________________.
D. A weak base is one that does not dissociate completely in an aqueous solution. In aqueous solution, both the
dissociation and the reverse reaction occur at the same time. ____________________ ions and _________ are formed
in the forward reaction but in the reverse reaction dissolved base molecules and water are produced.
+1
-1
NH3(aq) + H2O(l) →
← (NH4) (aq) + (OH) (aq)
1. Weak bases are poor _________________________.
PhET: Strong and Weak Acids and Bases
Data Table
Solution
Name
Acid or Base
pH
Conductivity
Strong
1.0M HCl
Strong
0.5M H2SO4
Strong
1.0M Ca(OH)2
Weak
0.1M CH3COOH
1.0M NH3
Strong or
Weak
Ammonia
0.1M NaOH
0.5M HF
Weak
Strong
Weak
Questions
1. Write an equation that represents the dissociation of each compound in solution. Use → for strong; and → for
←
weak.
2. For the solutions that you classified as acids, does the subscript for the hydrogen in these formulas seem to result in
additional ions in solution? Explain.
3. Why are strong acids also strong electrolytes?
4. Is every strong electrolyte also a strong acid? Explain.