Chemical Reactions and Types

Chemical Reactions

• A chemical reaction is a process that involves the transformation of one or more substances into new substances.
• Chemical reactions involve the breaking and forming of chemical bonds.

Types of Chemical Reactions

• Synthesis Reaction: A reaction in which two or more substances combine to form a new compound.
  • Example: 2H2 + O2 → 2H2O
• Decomposition Reaction: A reaction in which a single compound breaks down into two or more substances.
  • Example: 2H2O → 2H2 + O2
• Replacement Reaction: A reaction in which one element replaces another element in a compound.
  • Example: Zn + CuSO4 → ZnSO4 + Cu
• Combustion Reaction: A reaction in which a substance reacts with oxygen to produce heat and light.
  • Example: 2CH4 + 3O2 → 2CO2 + 3H2O

Chemical Equations

• A chemical equation is a symbolic representation of a chemical reaction.
• Chemical equations use chemical formulas and symbols to represent the reactants and products.

Balancing Chemical Equations

• Law of Conservation of Mass: Matter cannot be created or destroyed in a chemical reaction.
• To balance a chemical equation, coefficients are added in front of the formulas of the reactants and products to ensure that the number of atoms of each element is equal on both the reactant and product sides.

Steps to Balance a Chemical Equation

1. Write the unbalanced equation with the reactants on the left and products on the right.
2. Count the number of atoms of each element on both the reactant and product sides.
3. Add coefficients in front of the formulas of the reactants and products to balance the equation.
4. Check the equation to ensure that it is balanced.

Example of Balancing a Chemical Equation

• Unbalanced equation: Ca + O2 → CaO
• Balanced equation: 2Ca + O2 → 2CaO

Chemical Reactions

• Chemical reactions involve the transformation of one or more substances into new substances, resulting in the breaking and forming of chemical bonds.

Types of Chemical Reactions

• Synthesis Reaction: Combines two or more substances to form a new compound, e.g., 2H2 + O2 → 2H2O.
• Decomposition Reaction: Breaks down a single compound into two or more substances, e.g., 2H2O → 2H2 + O2.
• Replacement Reaction: Involves one element replacing another element in a compound, e.g., Zn + CuSO4 → ZnSO4 + Cu.
• Combustion Reaction: Reacts with oxygen to produce heat and light, e.g., 2CH4 + 3O2 → 2CO2 + 3H2O.

Chemical Equations

• A chemical equation is a symbolic representation of a chemical reaction using chemical formulas and symbols.
• Chemical equations must be balanced to ensure the Law of Conservation of Mass is upheld.

Balancing Chemical Equations

• The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction.
• Coefficients are added to the reactants and products to balance the equation, ensuring equal atoms of each element on both sides.

Steps to Balance a Chemical Equation

• Write the unbalanced equation with reactants on the left and products on the right.
• Count the number of atoms of each element on both sides.
• Add coefficients to balance the equation.
• Check the equation to ensure it is balanced.

Example of Balancing a Chemical Equation

• Unbalanced equation: Ca + O2 → CaO
• Balanced equation: 2Ca + O2 → 2CaO