Transcript 9.1 Acids and Bases Obj S1 and S2

9.1 Acids and Bases
Obj S1 and S2
Chemistry
Essential Questions
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What
What
What
What
What
What
are some properties of acids? Bases?
do they share?
is an acid? What is a base?
are conjugate acid-base pairs?
makes an acid/base weak? Strong?
is an amphoteric compound?
Properties of Acids and Bases
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Acids:
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Aqueous solutions of acids have a sour taste.
Acids react with metals to release hydrogen
gas.
Bases:
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Aqueous solutions of bases taste bitter.
Dilute aqueous solutions of bases feel
slippery.
Properties of Acids and Bases
(cont)
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Properties of both acids and bases:
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Change the color of acid-base indicators.
Conduct electrical current in solution
React to make salt and water in neutralization
reactions
Industrial Acids
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Sulfuric acid used in the production of
paints, papers, dyes, detergents and
automobile batteries.
Nitric acid used to make explosives,
rubber, plastics and pharmaceuticals.
Phosphoric acid used for manufacturing
fertilizers and animal feed.
Commonly used bases
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Ammonia, used as a household cleaner.
Sodium hydroxide commonly called lye.
Sodium hydrogen carbonate, baking soda.
Most other cleaning products.
Arrhenius Acid and Base definition
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In 1884 Svante Arrhenius (Sweden),
defined an acid as a material that can
release a proton or hydrogen ion (H+) in
an aqueous solution
He defined a base as a substance that
increased the concentration of hydroxide
ions (OH-) in aqueous solutions.
Bronsted-Lowry Acids and Bases
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In 1923 J.N. Bronsted and T.M. Lowry
independently defined an acid as a
molecule or ion that is a proton donor.
A base is a molecule or ion that is a
proton acceptor.
Bronsted-Lowry Acid-Base Reaction
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In a Bronsted-Lowry Acid-Base reaction
protons are transferred from one reactant
(acid) to another (base).
 H2SO4
acid
+ H2O H3O+ + HSO4base
conjugate conjugate
acid
base
Conjugate Acid-Base Pairs
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Conjugate base is the compound that remains
after a Bronsted-Lowry acid has given up a
proton.
Conjugate acid is the compound that is
formed when a Bronsted-Lowry base gains a
proton.
Conjugate acid-base pair is the combination
of acid/base with its conjugate.(see table 19.3
on p 591)
Conjugate Acid-Base Pairs (cont)
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HF + H2O
 F- + H3O+
The F- is the conjugate base of HF.
The H3O+ is the conjugate acid of water.
The F- and HF are conjugate pairs.
Water and the H3O+ are conjugate pairs.
Acid-Base conjugate pair strength
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Acid-Base conjugate pair strength are inversely
related so as one increases in strength the other
decreases in strength.
The stronger the acid/base the weaker its
conjugate and vice versa.
A strong acid would have a weak conjugate base
A strong conjugate acid is formed from a weak
base
Strong Acids and Bases
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What makes something a strong acid or
base?
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What makes something a weak acid or
base?
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ionizes (breaks apart into ions) completely in
aqueous solutions.
Do NOT completely ionize
P 605 lists common acids and bases
Amphoteric compounds
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Any species that can react as either an acid or
base is an amphoteric compound.
H2SO4 + H2O  H3O+ + HSO4
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NH3 + H2O  NH4+ + OH
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water accepts a proton thus is a base.
water donates a proton thus is an acid.
Water, therefore can be either an acid or a base
thus is amphoteric.
Essential Questions
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What
What
What
What
What
What
are some properties of acids? Bases?
do they share?
is an acid? What is a base?
are conjugate acid-base pairs?
makes an acid/base weak? Strong?
is an amphoteric compound?
9.1 Tracked Assignment
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Worksheet