acid-base reactions

14
Strong and Weak Acids Titration Common Acid Names Textbook section 4.3

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Acid-Base Reactions. Strong and Weak Acids Titration Common Acid Names. Textbook section 4.3. What is an ACID?. Defined: ACID Produces H + ions in water solution BASE Produces OH - ions in water solution. Acid Characteristics: Sour Taste (lemon) - PowerPoint PPT Presentation

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Page 1: Acid-Base Reactions

Strong and Weak Acids Titration Common Acid Names

Textbook section 4.3

Page 2: Acid-Base Reactions

Defined: ACID

Produces H+

ions in water solution

BASE Produces OH- ions in water solutionAcid Characteristics:

–Sour Taste (lemon)–Change Indicators Colors (litmus blue to red)

Page 3: Acid-Base Reactions

Strong Acids Ionize completely.

HCl (aq) H+ (aq) + Cl-

(aq)

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

5. H2SO4

6. HClO4

What are the names of these acids?

Check the partner of the “H” for a hint.

These must be memorized.

Page 4: Acid-Base Reactions

Weak acids ionize partially.General formula:

HB H+ + B-

Double arrow means reversible or it does not go to completion.

The equilibrium includes both products AND reactants.

Compare # of HCl ions in solution to HF ions in solution. Each w/ 1.0 M concentration.

Page 5: Acid-Base Reactions

Strong Bases Ionize Completely

NaOH Na+ + OH-

Hydroxides are commonly strong bases. Including:

LiOHKOHCa(OH)2

Sr(OH)2

Ba(OH)2

Page 6: Acid-Base Reactions

Produce OH- ions by reacting with the water.

NH3 aq + H2O aq NH4+

aq + OH-

aq

Pulling an H+, and leaving OH- behind.

We often write water HOH, to easily keep track of this water reaction

Include: ammonia NH3

amides R-NH2Weak bases are weak electrolytes. The bulb will light up but it will be dim

Page 7: Acid-Base Reactions

Mix and acid and base what happens?

The results depend upon the strength of the reactants. 3 TYPES:

1 Strong ACID - Strong BASE

2 Weak ACID – Strong BASE 3 Strong ACID – Weak BASE

Page 8: Acid-Base Reactions

Neutralization Reaction occurs The products are water, and an

aqueous salt. (ions)Consider Nitric Acid and Sodium

HydroxideH+ + NO3

- + Na+ + OH- Since they are “strong”, they

fully ionize

Animation of Nitric acid and Sodium Hydroxide

Neutralization produces Water and a salt.

Page 9: Acid-Base Reactions

Write the complete equation for this reaction

Identify any spectator ions and then write a net ionic equation.

2 step reaction occurs, The acid HF partially

dissociates to H+ + F-

Then the Base NaOH, which has dissociated to produce OH- ions (plus the Na+ ions)

The H+ and OH- combine to from water

Page 10: Acid-Base Reactions

The weak base gets “protonated”The strong acid is already dissociated into H+ and B-.

Consider ammonia and Hydrochloric AcidNH3 + H+ + Cl- NH4

+ + Cl-

Methylamine and Nitric AcidCH3NH2 + H+ CH3NH3

+

Page 11: Acid-Base Reactions

Poem That Makes Sense After Studying Predicting Reactions: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.

Page 12: Acid-Base Reactions

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.

Page 13: Acid-Base Reactions

Objective: 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

+

Page 14: Acid-Base Reactions

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

Bronsted-Lowry Acids:“ADP”

Acids donate protons Bases accept protons