1 some properties of acids þ produce h + (as h 3 o + ) ions in water (the hydronium ion is a...

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Some Properties of Acids

Produce H+ (as H3O+) ions in water (the hydronium ion is a

hydrogen ion attached to a water molecule)

Taste sour

React with metals to produce hydrogen gas

Electrolytes

React with bases to form a salt and water

pH is less than 7

Turns blue litmus paper to red

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What do acids do?

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Some Common Acids

HCl hydrochloric acid

HNO3 nitric acid

H2SO4 sulfuric acid

H3PO4 phosphoric acid

H2CO3 carbonic acid

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Strong Acids

• Strong acids completely ionize in water.

• For every mole of acid, there will be 1 mole of H+, so the concentration of H+ will be the same as the concentration of the acid.

• For Example:

HCl H+ + Cl- [0.03 M] [0.03M] [0.03 M]

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Strong Acids

HCl, HI, HBr, HNO3, H2SO4,

HClO4

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Weak Acids

• All weak acids form equilibrium systems in solution.

• For example:

H2CO3 (aq) <======> H+ (aq) + HCO3(aq)

• Since we have an equilibrium system, an equilibrium constant (Ka) can be written:

Ka = __[H+] [A-]___

[HA]

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Some Properties of Bases

Produce OH- ions in water

Taste bitter, chalky

Are electrolytes

Feel soapy, slippery

React with acids to form salts and water

pH greater than 7

Turns red litmus paper to blue “Basic Blue”

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Some Common Bases

NaOH sodium hydroxide lye

KOH potassium hydroxide liquid soap

Ba(OH)2 barium hydroxide stabilizer for plastics

Mg(OH)2 magnesium hydroxide “MOM” Milk of

magnesia

Al(OH)3 aluminum hydroxide Maalox (antacid)

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Strong Bases

• Strong bases completely ionize in water.

• For every mole of a base, there will be 1 mole of OH-, so the concentration of OH- will be the same as the concentration of the base.

• For Example:

NaOH Na+ + OH- [0.03 M] [0.03M] [0.03 M]

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Strong Bases

NaOH, KOH, LiOH, RbOH, CsOH, Ca(OH)2, Ba(OH)2,

Sr(OH)2

Strong bases completely ionized in water.

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HNO3, HCl, H2SO4 and HClO4 are among the only known strong acids.

Strong versus Weak Strong versus Weak Acids/BasesAcids/Bases

The strength of an acid (or base) is determined by the amount of IONIZATION.

The strength of an acid (or base) is determined by the amount of IONIZATION.

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Categorizing Acids/Bases: Categorizing Acids/Bases: Weak versus StrongWeak versus Strong

• Weak acids and bases do not completely ionize in water.

• Strong acids and bases completely ionize in water.

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Acids and Bases Acids and Bases TheoriesTheoriesAcids and Bases Acids and Bases TheoriesTheories

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Arrhenius Acids and Bases

• Acids – produce H+ ions (or hydronium ions H3O+)

• Bases – produce OH- ions

• (problem: some bases don’t have hydroxide ions!)

1515Arrhenius acid is a substance that produces H+ (H3O+) in water

Arrhenius base is a substance that produces OH- in water

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Brønsted – Lowry Acids and Bases

• Acids – proton donor

• Bases – proton acceptor

• A “proton” is really just a hydrogen atom that has lost it’s electron!

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A Brønsted-Lowry acid is a proton donorA Brønsted-Lowry base is a proton acceptor

acidconjugate

basebase conjugate

acid

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Bronsted-Lowry Definition

a. NH3(g) + H3O+(aq) → NH4

+(aq) + H2O

b. CH3OH(l) + NH2-(aq) → CH3O-

(aq) + NH3(g)

c. OH-(aq) + H3O+

(aq) → H2O + H2O

1919Lewis Acids and Lewis Acids and BasesBases

Lewis acid - a Lewis acid - a substance that substance that accepts an accepts an electron pairelectron pair

Lewis base - a Lewis base - a substance that substance that donates an donates an electron pairelectron pair

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The pH Scale

2121

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Calculating pH and pOH

pH = -log [H+] pOH = -log [OH-]

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2424

pHpH [H+][H+] [OH-][OH-] pOHpOH

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Neutralization

• Acid + Base– Ex:

HCl + NaOH NaCl + H2O

HNO3 + KOH KNO3 + H2O

• Neutralizations always result in a ________ and __________.

saltwater

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Base Ex.

Closing

Acid, Base, or Both?

Slippery

Soap

Tastes sour

Ca(OH)2

Conducts electricity

Corrosive to skin

Examples include citrus

fruits.

H2SO4

HNO3

Forms the H3O+ ion when

dissolved in water

Ionizes in water.

HCl

Litmus paper turns red

Forms the OH ion when

dissolved in water

pH < 7

pH > 7

Baking soda

Bitter taste

NaOH