Chemical Reactions and Equations

Definition

• A chemical reaction is the process by which one or more substances change into one or more new substances whose chemical and physical properties differ from those of the original substances.

Writing a Chemical Reaction

• Reactants are the elements or compounds you begin with

• Products are the elements or compounds you end with

Reactants Products“yield”

Numbers

• Superscripts show the charge of an ion

• Subscripts show the # of atoms in a compound

• Coefficients show the # of molecules

H+1 P-3

H2O C6H12O6

2NaCl 5H2O

Fill in the Blanks

Reactants

Yields

Product

Subscript Coefficient

Symbols

Symbols (cont.)

Symbols (cont.)

Signs of a Chemical Change

A gas is produced

A solidprecipitate is formed

Signs of a Chemical Change

Color Change

Temperature Change

Types of Chemical Reactions

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Synthesis

• A synthesis reaction starts with two or more reactants and ends up with one product.

Synthesis

Magnesium + Oxygen Magnesium oxide

2Mg + O2 2MgO

Synthesis

Sodium + Chlorine gas Salt

2Na + Cl2 2NaCl

http://youtu.be/2mzDwgyk6QM

Decomposition

• A decomposition reaction starts with one reactant and ends up with two or more products.

Decomposition

Calcium carbonate decomposes to produce calcium oxide and carbon dioxide.

CaCO3 CaO + CO2

Single Replacement

• A single-replacement reaction starts with two reactants and ends up with two products. An element takes the place of another element that’s in a compound.

Single ReplacementAluminum foil is placed

in a solution of copper II chloride which produces copper

metal and aluminum chloride solution.

2Al + 3CuCl2 3Cu + 2AlCl3

Double Replacement• A double-replacement reaction starts with two

reactants and ends up with two products. In this case both reactants and products are compounds. They simply change partners.

Double Replacement A solution of sodium

chloride is mixed with a solution of lead nitrate resulting in the production of sodium nitrate and lead chloride.

2NaCl + Pb(NO3)2 2NaNO3 + PbCl2

Combustion

• A combustion reaction always involves a hydrocarbon and oxygen as reactants and ends up with carbon dioxide and water as products.

What type of reaction is this?

2H2O 2H2 + O2

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

4P + 5O2 P4O10

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

2MgO 2Mg + O2

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

BaCl2 + H2S BaS + 2HCl

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement

What type of reaction is this?

2Al2O3 4Al + 3O2

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

Cl2 + 2NaBr Br2 + 2NaCl

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

What type of reaction is this?

3H2 + N2 2NH3

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

CaCl2 + 2KBr 2KCl + CaBr2

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement

What type of reaction is this?

H2O + MgO Mg(OH)2

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

2NH4CO3 2NH3 + H2O + CO2

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement

What type of reaction is this?

Cu + AgNO3 Ag + CuNO3

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement

What type of reaction is this?

2Al + 3CuCl2 3Cu + 2AlCl3

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement

What type of reaction is this?

C + 2H2 CH4

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

3NiO + 2Li3P 3Li2O + Ni3P2

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

What type of reaction is this?

CuCl2 + H2S 2HCl + CuS

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

2H3PO4 3H2O + P2O5

A)SynthesisB)DecompositionC)Single ReplacementD)Double Replacement

What type of reaction is this?

2Na + FeO Fe + Na2O

A)Synthesis

B)Decomposition

C)Single Replacement

D)Double Replacement