Types of chemical reactions

What is a chemical reaction?Recall…A chemical reaction: A process in which newsubstances with new properties are formed

The original substances present are called REACTANTS.

Reactants undergo a chemical change in a chemical

reaction.

The new substances formed in a chemical reaction arecalled PRODUCTS

Chemical ReactionsFive Types of Chemical Reactions:

5. Combustion

2. Decomposition

3. Single Displacement

4. Double Displacement

1. Synthesis

Evidence that a chemical reaction has taken place?

Color/Odor Change

Difficult to reverse

Release/Absorption of Energy (heat)

Formation of a gas or solid

1. Synthesis Reactions

Combination of two or more simple substances combining to form one more complex substance.

General Form: A + B AB

+

Mg(s) + O2(g) 22

Synthesis of Magnesium Oxide

C(s) + O2(g)

S(s) + O2(g)

Synthesis Reactions:

Other Examples

MgO

CO2(g)

SO2(g)

PracticePredict the products.

Na(s) + Cl2(g)

Mg(s) + F2(g)

Al(s) + F2(g)

NaCl(s)

MgF2(s)

AlF3(s)

22

2 3 2

• Now, balance them.

2. Decomposition Reactions

Breaking down large, complex molecules or ionic compounds into smaller, simpler entities.

General Form: AB A + B

+

Ex. Decomposition Reaction

Decomposition of Hydrogen Peroxide

2 2

Predict the products.

Fe2O3(s)

NaCl(s)

CaF2(s)

H2O2(l)O2(g) + H2O(l)

3. Single Displacement

Reaction of an element with a compound that produces a new element and new compound.

A + BC AC + B

3. Single DisplacementExample: Zn + CuCl2

ZnClClCu +

General: AB + C AC + B

ClClZn Cu+

Single Displacement of Zinc and Chlorine

Zn(s) + HCl(aq) ZnCl2(aq) + H2(g)2

Zinc chloride and hydrogen gas

form in this single displacement

reaction

Ex. Single Replacement Reaction

Single Replacement Reactions

Write and balance the following single replacement reaction equation:

• K(s) + HCl(aq)

• NaCl(s) + F2(g)

• Al(s)+ Cu(NO3)2(aq)

2

Cu(s)+ Al(NO3)3(aq)232

2NaF(s) + Cl2(g)

3

KCl(s) + H2(g)2 22

Examples2KBr (aq) + Cl2 (aq)

CuSO4 (aq) + Zn (s)

Mg (s) + 2HCl (aq)

4. Double Displacement

Reaction of two compounds, where the positiveand negative ions in their respective compounds switch places to form two new compounds. This can only happen with ionic compounds

AB + CD AD + CB

Double Displacement

A double displacement reaction only occurs if one of the following three results are seen:

a precipitate is formed (check solubility rules)

a gas is produced

a change of pH occurs (a neutralization reaction)

4. Double displacement

Example: MgO + CaS

General: AB + CD AD + CB

SO

Mg Ca+

OS

Mg Ca+

Double Replacement ReactionsThink about it like “foil”ing in algebra, first and last ions go together + inside ions go together

Example 1

AgNO3(aq) + NaCl(s) AgCl(s) + NaNO3(aq)

2

Example 2

K2SO4(aq) + Ba(NO3)2(aq) KNO3(aq) + BaSO4(s)

Double Displacement Reaction

Predict the products of the following Double Displacement Reactions

Pb(NO3)2(aq) + KI(aq) 22

AgNO3(aq) + NaCl(aq)

Ni(NO3)2 (aq) + NaOH(aq)2

PbI2(s) + KNO3(aq)

AgCl(s) + NaNO3(aq)

Ni(OH) 2(s) + NaNO3(aq)

Practice

1. HCl(aq) + AgNO3(aq)

2. CaCl2(aq) + Na3PO4(aq)

3. Pb(NO3)2(aq) + BaCl2(aq)

4. FeCl3(aq) + NaOH(aq)

5. H2SO4(aq) + NaOH(aq)

6. KOH(aq) + CuSO4(aq)

Predict the products:

More commonly known as burning

5. Combustion Reactions

Easily identified (release of heat)

Heat Fuel

For combustion 3 things need to be present:

Oxygen

5. Combustion Reactions

Sulphur (in gasoline):

S(s) + O2(g) SO2(g) + Heat

2 H2(l) + O2(l) 2 H2O(g) + Heat

Rocket Fuel:

Hydrocarbons (Eg: methane):CH4(g) + O2(g) CO2(g) + H2O (g)

Mixed PracticeState the type of the following reactions & predict the products.

1. BaCl2 + H2SO4

2. C6H12 + O2

3. Zn + CuSO4

4. Cs + Br2

5. FeCO3