Chapter%208%20Acids,%20Bases,%20and%20Salt

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Chapter 8Acids, Bases, and Salt

• Section 1
• Acids, Bases, and pH
• p. 256

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Objectives

• Compare acids and bases
• Understand the set up of the pH scale

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Acids And Bases Have Two Different Faces I.
Acids- any compound that increases the number of
hydronium (H3O) ions when dissolved in water
(they must ionize) A. Characteristics
1. Sour taste 2. Turn blue litmus paper red-
blue to red, acid (litmus is an
indicator) 3. Equation usually starts with an
H (HCl, H2SO4)
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B. Strong acids completely ionize and
form electrolytes 1. Electrolyte- substances
that conduct electricity when
dissolved in water
C. Weak acids form weak electrolytes D.
Concentrated acids can be very
dangerous a diluted solution is safer
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II. Bases- any compound that increases the number
of hydroxide (OH-) ions when dissolved in
water A. Characteristics
1. Bitter or soapy taste 2. Solutions feel
slippery 3. Turn red litmus paper blue 4.
Strong bases end in OH, weak
will form OH when dissolved in
water
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B. Strong bases- ionic compound that
contains a metal and OH- ion 1. When dissolved
in water they dissociate
completely 2. Attacks living tissue rapidly
when concentrated, can be more
dangerous than acids
C. Weak bases form OH- ions when
dissolved in water Acids Bases
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III. pH Indicates concentration of H30 ions
(think percent hydronium) pH is an indication
of moles/L of hydronium 1x10-7 mol/L
is a pH of 7
The exponent of the concentration is
the pH
Each step in the scale is a power of 10
increase/decrease in strength
Developed to test the acidity of beer
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? More H30
More OH- ?
Acids Balance of Ions Bases 0 1 2 3
4 5 6 7 8 9 10 11 12 13 14
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Homework