AP Chemistry
Elayne Tan
Chemistry: matter and its changes - Chapter 15 Study Guide
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Formulas
Strong Acids
pH = -log [H ]
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-pH
[H ] = 10
pX = -log X
pH + pOH = pKW = 14.00 (at 25°C)
Autoionization of water (equilibrium equation)
HNO3(aq)
HClO3(aq)
HClO4(aq)
HCl(aq)
HBr(aq)
HI(aq)
nitric acid
chloric acid
perchloric acid
hydrochloric acid
hydrobromic acid
hydroiodic acid
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Acidic solution
pH < 7.00
[H3O ] > [OH ]
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(Ion product constant of water)
Neutral solution
pH = 7.00
[H3O ] = [OH ]
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-14
KW = [H ][OH ] KW = 1.0 x 10 (at 25°C)
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Basic solution
pH > 7.00
[H3O ] < [OH ]
BrØnsted-Lowry concept of acids and bases is that acid-base reactions are proton transfer reactions
An acid is a proton donor
A base is a proton acceptor
Conjugate acid-base pair: two substances that differ
from each other only by one proton
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Conjugate acid: add one H
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Conjugate base: remove one H
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H3O is the strongest acid we will ever find in an aqueous solution
OH is the strongest base we will ever find in an aqueous solution
Amphiprotic: a compound that can act as either as a proton donor or proton acceptor
Amphoteric: a substance that can be either an acid or a base depending on the other substance present
The weaker the acid is, the
stronger its conjugate base
The stronger the acid is, the
weaker its conjugate base
Binary acids: have molecules made of just two elements, one being
hydrogen joined to another atom
 The strengths of the binary acids increase from left to right
within same period
 The strengths of binary acids increase from top to bottom
within the same group
Oxoacid: acid composed of hydrogen, oxygen, and another element
 For a given central atom, the acid strength of an oxoacid
increases with the number of oxygens held by the central
atom
 When the central atoms of oxoacids hold the same number
of oxygen atoms, the acid strength increases from bottom to
top within a group and from left to right within a period
Basic anhydrides: metal oxides that react with water to give hydroxide ions
Acidic anhydrides: non-metal oxides that react with water to give acidic solutions