8.1Acids and Bases
Introduction to Acids and Bases — AP CHEMISTRY Revision Notes & Topical Questions
5 min read 8 parts Lesson 6 of 16 2 quizzes
Lesson summary
8.1 Introduction to Acids and Bases — AP CHEMISTRY notes: Define acids and bases, identify conjugate pairs and water's role, and relate pH to concentration.Acid — a proton (H+) donorBase — a proton acceptorReaction — an acid-base reaction is a proton transfer from acid to baseAmp…
- Amphiprotic
- Autoionisation
- Neutral solution
- Definitions
- Strength relation
- Brønsted-Lowry acid
Section 1 of 8Brønsted-Lowry definitions
Acid
- Acid a proton (H+) donor
Base
- Base a proton acceptor
Reaction
- Reaction an acid-base reaction is a proton transfer from acid to base
Section 2 of 8Water
Amphiprotic
- Amphiprotic water can act as an acid or a base
Autoionisation
- 2H2O ⇌ H3O+ + OH−
Kw
- [H3O+][OH−] = 1.00 × 10-14 at 25 °C
Neutral solution
- [H3O+] = [OH−]
Section 3 of 8pH and pOH
Definitions
- Definitions pH = −log[H3O+] and pOH = −log[OH−]
Relation
- Relation pH + pOH = 14 at 25 °C
Acidic
- Acidic pH < 7; basic — pH > 7; neutral — pH = 7
Section 4 of 8Conjugate acid-base pairs
Pair
- Pair two species differing by one proton
Strength relation
- Strength relation a strong acid has a weak conjugate base; a weak acid has a stronger conjugate base
Example
- HBr/Br− and H3O+/H2O in HBr + H2O → Br− + H3O+
Section 5 of 8Strong and weak
| Type | Ionisation | Example |
|---|---|---|
| Strong acid | Complete | HCl, HNO3 |
| Weak acid | Partial | CH3COOH |
| Strong base | Complete dissociation | NaOH, Ba(OH)2 |
| Weak base | Partial | NH3 |
Section 6 of 8More from the specification
More from the specification
Relative strength order of Brønsted acids
- Relative strength order of Brønsted acids measuring dissociation constants establishes an empirical acidity order ranging from strong mineral acids to weak organics.
Charge
- Q = It, measured in coulombs.What the symbols mean: Q = charge (C) · I = current (A) · t = time (s)
Reactants
- The substances that react together at the start of a reaction.
Theory
- A tested hypothesis that is widely accepted.
Aqueous
- Dissolved in water.
Section 7 of 8Key terms
| Term | Meaning |
|---|---|
| Brønsted-Lowry acid | Proton donor. |
| Brønsted-Lowry base | Proton acceptor. |
| Amphiprotic | Able to donate or accept a proton. |
| Kw | Ionic product of water. |
| Conjugate pair | Two species related by one proton. |
Section 8 of 8Exam technique
Avoid these mistakes
Saying a pH of 0 is not possible — very concentrated acids can have pH ≤ 0.
Calling any species with H a Brønsted-Lowry acid — it must be able to donate a proton.
Saying water is only a base.
Marked practiceQuizzes for this lesson
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