Special Reactions

Remember these!!!

Acid-Base (Neutralization)

• When an acid is mixed with a base, a salt and water are formed.

HNO3 (aq) + NaOH (aq) NaNO3 (aq) + HOH (l)

acid base ionicsalt

water

Nonmetal Oxides in Water

• A nonmetal oxide is known as an acid anhydride. When mixed with water, it forms an acid. (This is the cause of acid rain.)

SO3(g) + H2O(l) H2SO4(aq)

Metal Oxides in Water

• If a metal oxide, also called a base anhydride, is mixed with water, a base is formed.

Na2O(s) + H2O(l) 2 NaOH(aq)

Combustion

• Combustion of substances containing carbon will form carbon dioxide gas.

2 CO(g) + O2(g) 2 CO2(g)

• Combustion of substances containing carbon and hydrogen will form carbon dioxide and water.

CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)

Incomplete Combustion

• If not enough oxygen is present when burning a hydrocarbon, the result is the formation of carbon monoxide instead of carbon dioxide.

2 CH4(g) + 3 O2(g) 2 CO(g) + 4 H2O(g)

Chlorates

• When heated, chlorates will decompose into their respective chloride salts and oxygen gas.

2 KClO3(s) 2 KCl(s) + 3 O2(g)

Mg(ClO3)2 (s) MgCl2(s) + 3 O2(g)

2 Al(ClO3)3(s) 2 AlCl3(s) + 9 O2(g)

Carbonates

• Carbonates will often decompose into the metal oxide and carbon dioxide gas.

K2CO3(s) K2O(s) + CO2(g)

MgCO3(s) MgO(s) + CO2(g)

Al2(CO3)3(s) Al2O3(s) + 3 CO2(g)

Carbonic Acid

•Carbonic acid, H2CO3, will spontaneously decompose into carbon dioxide and water.

H2CO3(aq) CO2(g) + H2O(l)

If carbonic acid is a product of a reaction, it will decompose. One should NEVER have carbonic acid as a final product!

Carbonates and acids

• When a carbonate is mixed with an acid, carbonic acid is usually a product. Recall that carbonic acid spontaneously decomposes into carbon dioxide and water!

• 2 HCl (aq) + MgCO3(aq) MgCl2(aq) + H2CO3 (aq)

2 HCl (aq) + MgCO3 (aq) MgCl2 (aq) + H2O (l) + CO2 (g)

Oxidation and Reduction Oxidation and Reduction (Redox)(Redox)

• Electrons are transferred

11

2

00

22

ClNaClNa

Each sodium atom loses one electron:

eNaNa10

Each chlorine atom gains one electron:

10 CleCl

How do you know if itHow do you know if it’’s s Oxidation or Reduction?Oxidation or Reduction?

GGainain EElectronslectrons = = RReductioneduction

An old memory device for An old memory device for oxidation and reduction goes oxidation and reduction goes like this…like this…

LEOLEO says says GERGER

LLoseose EElectronslectrons = = OOxidationxidation

LEO says GER :LEO says GER :

eNaNa10

Lose Electrons = Oxidation

Sodium is oxidized

Gain Electrons = Reduction

10 CleCl Chlorine is reduced

Reducing Agents and Oxidizing Reducing Agents and Oxidizing AgentsAgents

  The substance reduced is the oxidizing agent   The substance oxidized is the reducing agent

eNaNa10

10 CleCl

Sodium is oxidized – it is the reducing agent

Chlorine is reduced – it is the oxidizing agent