Types of Reactions

precipitate: a solid product that forms in an aqueous solution reaction

Na2CO3 + Ca(NO3)2 CaCO3 +(aq)(aq) 2 (aq)(s) NaNO3

ppt

clearNa2CO3

solution

clearCa(NO3)2

solution

cloudy solutioncontaining CaCO3(s)

and NaNO3(aq)

“chunks”“sinkies”“floaties”

Key Terms

Term Definition In an Equation

soluble able to be dissolved (aq)

insoluble does not dissolve in solution (or water)

(ins)

precipitate an insoluble solid formed when two solutions are mixed

(s)

Using Solubility Rules – Most solubility rules are written based on the

negative ion or anion •

Soluble compounds contain… Insoluble compounds contain…

For these compounds, common exceptions are INSOLUBLE.

For these compounds, common exceptions are SOLUBLE.

How to Determine if a Compound is Soluble or Insoluble?

• Find the anion in the compound.• Find the rule in the solubility tables that

matches the ion.• Double check to make sure the cation isn’t

listed as an exception.

Predict if the following compounds are soluble or insoluble.

– CaCl2

– CuSO4

– Al2(CrO4)3

– Mg(OH)2

– AgCl

– SrS

Soluble

Soluble

Insoluble

InsolubleInsoluble

Soluble

Predicting if a Precipitate will Form

–Precipitate reactions are precipitation reactions.

–In order for a reaction to be a precipitation reaction, there must be• one solid product, which is the precipitate,

and• both reactants should be aqueous solutions

Determine which reactions are precipitation reactions or

reactions that will form a precipitate.

• Pb(NO3)2 + KI PbI2 + KNO3

• (NH4)2CO3 + K2S K2CO3 + (NH4)2S

• Ag + Cu(NO3)2 AgNO3 + Cu

• Ba(OH)2 + Fe(ClO4)3 Ba(ClO4)2 + Fe(OH)3

(aq) (aq) (aq)(s)

(aq) (aq) (aq)(aq)

(s) (aq) (s)(aq)

(aq) (aq) (s)(aq)

YES

NO

NO

YES

Neutralization Reaction

• A reaction between and acid and a base which results in the production of a salt and water.

9

ACID + BASE = SALT + WATERHCl(aq) + NaOH(aq) = H2O(l) + NaCl(aq)

Mg(OH)2(s) + 2HCl(aq) = MgCl2(aq) + 2H2O(l)

Reduction-Oxidation ReactionREDOX

• A reaction in which electrons are transferred from one species to another.

• Oxidation means the loss of electrons.• Reduction means the gain of electrons.

LEO says GER

Loss Electrons = Oxidation

Gain Electrons = Reduction

Many oxidation-reduction reactions are single replacement reactions

Oxidation Reduction Reactions(Redox)

Each sodium atom loses one electron:

Each chlorine atom gains one electron:

11

2

00

22

ClNaClNa

eNaNa10

10 CleCl

LEO says GER :

Lose Electrons = Oxidation

Sodium is oxidized

Gain Electrons = Reduction

Chlorine is reduced

eNaNa10

10 CleCl

Rules for Assigning Oxidation NumbersRules 1 & 2

1. The oxidation number of any uncombined element is zero

2. The oxidation number of a monatomic ion equals its charge

11

2

00

22

ClNaClNa

Rules for Assigning Oxidation NumbersRules 3 & 4

3. The oxidation number of oxygen in compounds is -2

4. The oxidation number of hydrogen in compounds is +1

2

2

1

OH

Rules for Assigning Oxidation Number Rule 5

5. The sum of the oxidation numbers in the formula of a compound is 0

2(+1) + (-2) = 0 H O

(+2) + 2(-2) + 2(+1) = 0 Ca O H

2

2

1

OH 2

122

)(

HOCa

Rules for Assigning Oxidation NumbersRule 6

6. The sum of the oxidation numbers in the formula of a polyatomic ion is equal to its charge

X + 3(-2) = -1N O

X = +5 X = +6

X + 4(-2) = -2S O

3

2?

ON

24

2?

OS

Assigning Oxidation StatesExample: Assign oxidation states to all atoms in thefollowing.a. CO2 O = b. SF6 F = c. NO3

- O = d. MnO4

- O = e. HSO3

- O = f. H2O H = g. Li3N Li =

-2 (for each oxygen); C = +4-1 (for each fluorine); S = +6

-2 (each oxygen); N = +5

-2 (each oxygen); Mn = +7

-2 (each oxygen); H = +1, S = +4

+1 (each); O = -2

+1 (each); N = -3