Balancing Chemical Equations

Balancing Equations

• A balanced equation has the same number of atoms of each element on both the reactant and product sides.
• To balance an equation, coefficients (numbers in front of formulas of reactants or products) are added to the equation, not subscripts (numbers within formulas).
• Steps to balance an equation:
  1. Write the unbalanced equation with the reactants on the left and products on the right.
  2. Count the atoms of each element on both sides of the equation.
  3. Add coefficients to balance the equation, starting with the elements that appear in the greatest number of formulas.
  4. Check the equation to ensure it is balanced.

Types Of Reactions

• Synthesis Reactions: Two or more reactants combine to form a single product.
  • Formula: A + B → AB
• Decomposition Reactions: A single reactant breaks down into two or more products.
  • Formula: AB → A + B
• Replacement Reactions: One element replaces another element in a compound.
  • Formula: A + BC → AC + B
• Combustion Reactions: A substance reacts with oxygen to produce heat and light.
  • Formula: 2CH₄ + 3O₂ → 2CO₂ + 3H₂O

Oxidation and Reduction

• Oxidation: The loss of one or more electrons by an atom, molecule, or ion.
• Reduction: The gain of one or more electrons by an atom, molecule, or ion.
• Oxidizing Agent: A species that causes oxidation, often by accepting electrons.
• Reducing Agent: A species that causes reduction, often by donating electrons.

Redox Reactions

• A redox reaction is a reaction that involves both oxidation and reduction.
• Oxidation Number: A number assigned to an atom in a molecule to indicate its oxidation state.
• Redox Reaction Types:
  • Combustion Reaction: A reaction that involves the oxidation of a substance by oxygen.
  • Disproportionation Reaction: A reaction in which a single reactant is both oxidized and reduced.
  • Single Displacement Reaction: A reaction in which an element displaces another element from a compound.

Balancing Equations

• A balanced equation has the same number of atoms of each element on both the reactant and product sides.
• Coefficients (numbers in front of formulas) are added to balance an equation, not subscripts (numbers within formulas).
• Steps to balance an equation: write the unbalanced equation, count atoms of each element on both sides, add coefficients to balance, and check the equation.

Types Of Reactions

Synthesis Reactions

• Definition: Two or more reactants combine to form a single product.
• Formula: A + B → AB.

Decomposition Reactions

• Definition: A single reactant breaks down into two or more products.
• Formula: AB → A + B.

Replacement Reactions

• Definition: One element replaces another element in a compound.
• Formula: A + BC → AC + B.

Combustion Reactions

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

Oxidation and Reduction

Oxidation

• Definition: The loss of one or more electrons by an atom, molecule, or ion.

Reduction

• Definition: The gain of one or more electrons by an atom, molecule, or ion.

Oxidizing Agent

• Definition: A species that causes oxidation, often by accepting electrons.

Reducing Agent

• Definition: A species that causes reduction, often by donating electrons.

Redox Reactions

• Definition: A reaction that involves both oxidation and reduction.

Oxidation Number

• Definition: A number assigned to an atom in a molecule to indicate its oxidation state.

Redox Reaction Types

Combustion Reaction

• Definition: A reaction that involves the oxidation of a substance by oxygen.

Disproportionation Reaction

• Definition: A reaction in which a single reactant is both oxidized and reduced.

Single Displacement Reaction

• Definition: A reaction in which an element displaces another element from a compound.

Learn how to balance a chemical equation by adding coefficients to ensure the same number of atoms of each element on both reactant and product sides. Follow the steps to balance an equation.