reactions in aqueous solution: acids (section 4.3)

Reactions in Aqueous Solution: Acids (section 4.3)

Build the following molecules using the plastic molecular models:

• Nitric Acid • Perchloric Acid• Hydrochloric Acid• 3 or 4 water molecules

Find meanings for these:• Amphoteric

• Bronsted-Lowry

• Aqueous

• Conjugate

• Hydronium

What is an ACID?

Acid Characteristics:

Taste:

Indicator:

Acid Definitions:Bronsted-Lowry

Arrhenius: Acids put H+ into water Bases put OH- into water

Bronsted-Lowry Acids:“ADP”

Acids donate protons Bases accept protons

The Bronsted-Lowry definition is broader (more inclusive) than the Arrhenius definition.

Strong Acids• Strong Acids Ionize completely in water. (100%)• HCl (aq) H+

(aq) + Cl- (aq)

• The strong ACIDS are:1. HCl2. HBr3. HI4. HNO3

5. H2SO4

6. HClO4

Give formula and name of the 6 strong acids.

Weak AcidsWeak acids ionize partially in water. Less than 10%, usually much less than 1% ionization.

General formula:

Double arrow means reversible or it does not go to completion.The equilibrium includes both products AND reactants.

Strong BasesStrong Bases Ionize Completely in water. (100%)NaOH Na+ + OH-

•Always soluble hydroxides and Ca, Ba, Sr hydroxides are strong bases. Including:LiOHKOHCa(OH)2

Sr(OH)2

Ba(OH)2

Weak BasesProduce OH- ions by reacting with the water. Less than 100% ionized.

NH3 aq + H2O aq NH4+

aq + OH- aq

Include: ammonia NH3

amides R-NH2

Acid-Base Reactions

3 TYPES:• 1 Strong ACID - Strong BASE• 2 Weak ACID – Strong BASE• 3 Strong ACID – Weak BASE

Strong ACID + Strong BASE

“Neutralization” ReactionThe products are water, and an aqueous salt. (ions)

Weak Acid – Strong Base

Weak acid only partially ionized.Strong base fully ionized.The H+ and OH- combine to form water.

All H+ gets “used up” (reacted). The anion (salt of the weak acid is not used up or

reacted).

Strong ACID – Weak BASEThe weak base gets “protonated” (H+ added to the base)

Ammonia and Hydrochloric AcidNH3 + H+ + Cl- NH4

+ + Cl-

Cross out the spectators

Methylamine and Nitric AcidCH3NH2 + H+ + NO3

- CH3NH3

+ + NO3-

Cross out the spectators

• Johnny finding life a bore, drank some H2SO4.Johnny's father, an M.D., gave him CaCO3.Johnny's neutralized, it's true,But now he's full of CO2.

Find meanings for these:• Amphoteric

• Bronsted-Lowry

• Aqueous

• Conjugate

• Hydronium

Acid Base Titration

An standardized acid (known concentration) may be used to determine the unknown strength of a base. (or visa-versa)

Using an indicator (solution that changes color)

you can know when the added solution is exactly equal to the unknown.

this is known as the EQUILVALENCE POINT.

Acid-Base titrationObjective: Determine the equivalence point.

Equivalence point nOH- = nH

+

If 25.00mL of 0.0800M NaOH is needed to react with 10.00 mL of HCl. What is the molarity of HCl?

1. Write the reaction2. Use M1V1=M2V2

In this case the formula could be written MOH- VOH

- = MH+VH

+