Chemical Reactions and Equations

Interactive Learning Module for Grade 9-10 Students

Educational Videos

Interactive Flashcards

Click on each card to reveal the answer!

What is a Chemical Equation?
A symbolic representation of a chemical reaction showing reactants and products with their chemical formulas
What is a Balanced Chemical Equation?
An equation where the number of atoms of each element is equal on both reactant and product sides
What is a Combination Reaction?
A reaction where two or more reactants combine to form a single product (A + B → AB)
What is a Decomposition Reaction?
A reaction where a single compound breaks down into two or more simpler substances (AB → A + B)
What is Displacement Reaction?
A reaction where a more reactive element displaces a less reactive element from its compound (A + BC → AC + B)
What is Double Displacement?
A reaction where ions of two compounds exchange places to form two new compounds (AB + CD → AD + CB)
What is an Endothermic Reaction?
A reaction that absorbs heat energy from surroundings, causing temperature to decrease
What is an Exothermic Reaction?
A reaction that releases heat energy to surroundings, causing temperature to increase
What is Oxidation?
Loss of electrons, gain of oxygen, or loss of hydrogen by a substance
What is Reduction?
Gain of electrons, loss of oxygen, or gain of hydrogen by a substance

Visual Diagrams

Types of Chemical Reactions

flowchart TD A[Chemical Reactions] --> B[Combination Reaction] A --> C[Decomposition Reaction] A --> D[Displacement Reaction] A --> E[Double Displacement] A --> F[Redox Reactions] B --> B1[A + B → AB] C --> C1[AB → A + B] D --> D1[A + BC → AC + B] E --> E1[AB + CD → AD + CB] F --> F1[Oxidation & Reduction] style A fill:#4a90e2,stroke:#333,stroke-width:3px,color:#fff style B fill:#ff6b6b,stroke:#333,stroke-width:2px,color:#fff style C fill:#4ecdc4,stroke:#333,stroke-width:2px,color:#fff style D fill:#45b7d1,stroke:#333,stroke-width:2px,color:#fff style E fill:#96ceb4,stroke:#333,stroke-width:2px,color:#fff style F fill:#feca57,stroke:#333,stroke-width:2px,color:#fff

Components of Chemical Equations

mindmap root((Chemical Equation)) Reactants Starting Materials Left Side of Arrow What We Begin With Products Final Substances Right Side of Arrow What We Get Coefficients Balance Numbers Show Quantity Conservation of Mass States Solid (s) Liquid (l) Gas (g) Aqueous (aq) Arrow Direction of Reaction Yields/Produces Separates Sides

Reaction Types Summary

Reaction Type General Form Example Key Characteristics
Combination A + B → AB 2H₂ + O₂ → 2H₂O Two or more reactants form one product
Decomposition AB → A + B 2H₂O → 2H₂ + O₂ One reactant breaks into multiple products
Displacement A + BC → AC + B Zn + CuSO₄ → ZnSO₄ + Cu More reactive element displaces less reactive
Double Displacement AB + CD → AD + CB AgNO₃ + NaCl → AgCl + NaNO₃ Exchange of ions between compounds
Precipitation Solution + Solution → Precipitate Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃ Insoluble solid forms from solutions

Energy Changes in Reactions

Exothermic Reactions

Release energy (heat) to surroundings

Examples: Combustion, Respiration

Feel: Warm or hot

Endothermic Reactions

Absorb energy (heat) from surroundings

Examples: Photosynthesis, Melting ice

Feel: Cool or cold

Oxidation and Reduction

  • Oxidation: Loss of electrons, gain of oxygen, loss of hydrogen
  • Reduction: Gain of electrons, loss of oxygen, gain of hydrogen
  • Redox Reactions: Involve both oxidation and reduction simultaneously
  • Memory Aid: OIL RIG (Oxidation Is Loss, Reduction Is Gain)

Equation Balancer Game

Balance the following chemical equation by entering the correct coefficients:

H₂ + O₂ → H₂O

Reaction Simulator

Drag molecules to simulate different types of reactions:

H₂
H₂
O₂
Drop molecules here to form products

Reaction Type Classifier

Identify the type of reaction:

2Mg + O₂ → 2MgO

Knowledge Assessment

Question 1 of 10

Which law must be followed when balancing chemical equations?

Law of Conservation of Energy
Law of Conservation of Mass
Law of Conservation of Momentum
Law of Definite Proportions

Practice Problems

Balancing Equations Practice

Instructions: Balance the following equations by determining the correct coefficients.

  1. ___ Al + ___ O₂ → ___ Al₂O₃
  2. ___ C₄H₁₀ + ___ O₂ → ___ CO₂ + ___ H₂O
  3. ___ Fe + ___ HCl → ___ FeCl₃ + ___ H₂
  4. ___ Ca(OH)₂ + ___ HNO₃ → ___ Ca(NO₃)₂ + ___ H₂O
  5. ___ NH₃ + ___ O₂ → ___ NO + ___ H₂O

Real-World Applications

Photosynthesis

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Plants convert carbon dioxide and water into glucose using sunlight energy.

Combustion

CH₄ + 2O₂ → CO₂ + 2H₂O

Natural gas burning in stoves and heating systems releases energy.

Cellular Respiration

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Our cells break down glucose to release energy for body functions.

Rusting

4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃

Iron reacts with oxygen and moisture to form rust.