Chemical Reactions and Equations

Chemical Reaction

A chemical reaction is a process in which one or more substances (reactants) are converted into new substances (products). This process involves the breaking and forming of chemical bonds.

Types of Chemical Reactions

• Synthesis Reaction: Two or more reactants combine to form a single product.
• Decomposition Reaction: A single reactant breaks down into two or more products.
• Replacement Reaction: One element replaces another element in a compound.
• Combustion Reaction: A reaction involving oxygen, often resulting in heat and light.

Chemical Equation

A chemical equation is a representation of a chemical reaction using chemical formulas and symbols.

Components of a Chemical Equation

• Reactants: The substances that are converted into new substances.
• Products: The new substances formed during the reaction.
• Arrow: Indicates the direction of the reaction (→).
• Coefficients: Numbers in front of formulas indicating the mole ratio of reactants and products.
• State Symbols: Indicate the physical state of reactants and products (s, l, g, or aq).

Writing a Chemical Equation

1. Write the formulas of the reactants on the left side of the arrow.
2. Write the formulas of the products on the right side of the arrow.
3. Balance the equation by adding coefficients to ensure equal numbers of atoms of each element.

Balancing a Chemical Equation

• Count Atoms: Count the number of atoms of each element on both sides of the equation.
• Add Coefficients: Add coefficients to ensure equal numbers of atoms of each element.
• Check and Repeat: Check the equation and repeat the process until balanced.

Examples of Chemical Equations

• Synthesis Reaction: 2H2 + O2 → 2H2O
• Decomposition Reaction: 2H2O → 2H2 + O2
• Replacement Reaction: Zn + CuSO4 → ZnSO4 + Cu