Chemical Reactions: Synthesis and Single Displacement

Chemical Reactions

Synthesis Reactions

• A reaction where two or more substances combine to form a new compound
• General equation: A + B → AB
• Example: 2H2 + O2 → 2H2O (hydrogen and oxygen combine to form water)
• Characteristics:
  • Two reactants
  • One product
  • Formation of a new bond

Single Displacement Reactions

• A reaction where one element displaces another element from a compound
• General equation: A + BC → AC + B
• Example: Zn + CuSO4 → ZnSO4 + Cu (zinc displaces copper from copper sulfate)
• Characteristics:
  • One reactant is an element
  • One reactant is a compound
  • Displacement of an element

Combustion Reactions

• A reaction where a substance reacts with oxygen to produce heat and light
• General equation: Fuel + O2 → Products (CO2, H2O, etc.)
• Example: 2CH4 + 3O2 → 2CO2 + 3H2O (methane combusts with oxygen to produce carbon dioxide and water)
• Characteristics:
  • Involves oxygen as a reactant
  • Produces heat and light
  • Often involves a hydrocarbon fuel

Decomposition Reactions

• A reaction where a single compound breaks down into two or more simpler substances
• General equation: AB → A + B
• Example: 2H2O → 2H2 + O2 (water decomposes into hydrogen and oxygen)
• Characteristics:
  • One reactant
  • Two or more products
  • Breakdown of a compound

Double Displacement Reactions

• A reaction where two compounds exchange partners to form two new compounds
• General equation: AB + CD → AD + CB
• Example: NaCl + AgNO3 → NaNO3 + AgCl (sodium chloride and silver nitrate react to form sodium nitrate and silver chloride)
• Characteristics:
  • Two reactants
  • Two products
  • Exchange of ions between reactants

Chemical Reactions

Synthesis Reactions

• Two or more substances combine to form a new compound
• General equation: A + B → AB
• Example: 2H2 + O2 → 2H2O (hydrogen and oxygen combine to form water)
• Characteristics: two reactants, one product, formation of a new bond

Single Displacement Reactions

• One element displaces another element from a compound
• General equation: A + BC → AC + B
• Example: Zn + CuSO4 → ZnSO4 + Cu (zinc displaces copper from copper sulfate)
• Characteristics: one reactant is an element, one reactant is a compound, displacement of an element

Combustion Reactions

• A substance reacts with oxygen to produce heat and light
• General equation: Fuel + O2 → Products (CO2, H2O, etc.)
• Example: 2CH4 + 3O2 → 2CO2 + 3H2O (methane combusts with oxygen to produce carbon dioxide and water)
• Characteristics: involves oxygen as a reactant, produces heat and light, often involves a hydrocarbon fuel

Decomposition Reactions

• A single compound breaks down into two or more simpler substances
• General equation: AB → A + B
• Example: 2H2O → 2H2 + O2 (water decomposes into hydrogen and oxygen)
• Characteristics: one reactant, two or more products, breakdown of a compound

Double Displacement Reactions

• Two compounds exchange partners to form two new compounds
• General equation: AB + CD → AD + CB
• Example: NaCl + AgNO3 → NaNO3 + AgCl (sodium chloride and silver nitrate react to form sodium nitrate and silver chloride)
• Characteristics: two reactants, two products, exchange of ions between reactants

Chemical Reactions

Synthesis Reactions

• Combines two or more substances to form a new compound
• General equation: A + B → AB
• Examples:
  • 2H2 + O2 → 2H2O (water formation)
  • CaO + H2O → Ca(OH)2 (calcium hydroxide formation)

Single Displacement Reactions

• One element displaces another element from a compound
• General equation: A + BC → AC + B
• Examples:
  • Zn + CuSO4 → ZnSO4 + Cu (zinc displaces copper)
  • 2K + CaCl2 → 2KCl + Ca (potassium displaces calcium)

Oxidation-Reduction (Redox) Reactions

• Involve the transfer of electrons between atoms or molecules
• Oxidation: loss of electrons (increase in oxidation state)
• Reduction: gain of electrons (decrease in oxidation state)
• General equation: oxidized species + reduced species → products
• Examples:
  • 2CuO → 2Cu + O2 (copper oxide reduction)
  • 2H2 + O2 → 2H2O (hydrogen combustion)

Combustion Reactions

• A substance reacts with oxygen to produce heat and light
• Often involves the reaction of a fuel with oxygen
• General equation: fuel + O2 → products
• Examples:
  • 2CH4 + 3O2 → 2CO2 + 3H2O (methane combustion)
  • 2C2H6 + 7O2 → 4CO2 + 6H2O (ethane combustion)

Decomposition Reactions

• A single compound breaks down into two or more substances
• General equation: AB → A + B
• Examples:
  • 2H2O → 2H2 + O2 (water decomposition)
  • CaCO3 → CaO + CO2 (calcium carbonate decomposition)

Stoichiometry

• Stoichiometry is the study of quantitative relationships between reactants and products in chemical reactions.
• It involves calculating the amounts of substances required for a reaction to occur.
• Stoichiometric coefficients are used to balance chemical equations.
• The law of definite proportions states that a chemical compound always contains the same proportion of elements by mass, regardless of its source.

Reaction Types

Synthesis (Combination) Reactions

• Two or more substances combine to form a new compound.
• Example: 2H2 + O2 → 2H2O

Decomposition Reactions

• A single substance breaks down into two or more substances.
• Example: 2H2O → 2H2 + O2

Replacement (Single Displacement) Reactions

• One element replaces another element in a compound.
• Example: Zn + CuSO4 → ZnSO4 + Cu

Combustion Reactions

• A substance reacts with oxygen to produce heat and light.
• Example: 2CH4 + 3O2 → 2CO2 + 3H2O

Neutralization Reactions

• An acid reacts with a base to form a salt and water.
• Example: HCl + NaOH → NaCl + H2O