A. Concepts of Chemical reactions A chemical reaction is a process in which one or more substances, called reactants, are changed into new substances called products. During a reaction, atoms are rearranged as chemical bonds are broken and formed. The key concepts are: 1.Reactants – substances that start the reaction. 2.Products – new substances formed after the reaction. 3.Chemical bonds – bonds may break or form during a reaction. B. Types of Chemical Reactions - Decomposition Reaction A decomposition reaction is a chemical reaction in which one compound breaks down into two or more simpler substances. General pattern AB → A + B Example 2H₂O₂ → 2H₂O + O₂ Hydrogen peroxide breaks down into water and oxygen gas. “A decomposition reaction is basically the opposite of combining substances. Instead of several substances forming one product, one compound breaks apart into simpler substances. 2. Acid + Carbonate Reaction - An acid-carbonate reaction occurs when an acid reacts with a carbonate, producing a salt, water, and carbon dioxide gas. General pattern Acid + Carbonate → Salt + Water + CO₂ Example: 2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂ Hydrochloric acid reacts with calcium carbonate to produce calcium chloride, water, and carbon dioxide. “When an acid reacts with a carbonate, carbon dioxide gas is produced. That's why we often see bubbling or fizzing during this type of reaction.” 3. Acid on Metal reactions - An acid-metal reaction occurs when an acid reacts with a metal, producing a salt and hydrogen gas. General pattern Acid + Metal → Salt + H₂ Example: 2HCl + Mg → MgCl₂ + H₂ Hydrochloric acid reacts with magnesium to produce magnesium chloride and hydrogen gas. “When certain metals react with acids, the metal replaces the hydrogen in the acid. This produces a salt and releases hydrogen gas, which can be observed as bubbles.” 4. Combustion Reaction - A combustion reaction is a chemical reaction in which a substance reacts rapidly with oxygen, usually releasing heat and often light. General pattern For a hydrocarbon: Hydrocarbon + O₂ → CO₂ + H₂O + Energy Example: CH₄ + 2O₂ → CO₂ + 2H₂O + Energy Methane reacts with oxygen and produces carbon dioxide, water, heat, and light. “Combustion is basically burning. A substance reacts with oxygen and releases energy, usually in the form of heat and sometimes light.” Easy way to remember: 🔥 Fuel + Oxygen → Energy Real- life examples: -burning wood -cooking with a stove
A. Concepts of Chemical reactions
A chemical reaction is a process in which one or more substances, called reactants, are changed into new substances called products. During a reaction, atoms are rearranged as chemical bonds are broken and formed.
The key concepts are:
1.Reactants – substances that start the reaction.
2.Products – new substances formed after the reaction.
3.Chemical bonds – bonds may break or form during a reaction.
B. Types of Chemical Reactions
- Decomposition Reaction
A decomposition reaction is a chemical reaction in which one compound breaks down into two or more simpler substances.
General pattern
AB → A + B
Example
2H₂O₂ → 2H₂O + O₂
Hydrogen peroxide breaks down into water and oxygen gas.
“A decomposition reaction is basically the opposite of combining substances. Instead of several substances forming one product, one compound breaks apart into simpler substances.
2. Acid + Carbonate Reaction
- An acid-carbonate reaction occurs when an acid reacts with a carbonate, producing a salt, water, and carbon dioxide gas.
General pattern
Acid + Carbonate → Salt + Water + CO₂
Example:
2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂
Hydrochloric acid reacts with calcium carbonate to produce calcium chloride, water, and carbon dioxide.
“When an acid reacts with a carbonate, carbon dioxide gas is produced. That's why we often see bubbling or fizzing during this type of reaction.”
3. Acid on Metal reactions
- An acid-metal reaction occurs when an acid reacts with a metal, producing a salt and hydrogen gas.
General pattern
Acid + Metal → Salt + H₂
Example:
2HCl + Mg → MgCl₂ + H₂
Hydrochloric acid reacts with magnesium to produce magnesium chloride and hydrogen gas.
“When certain metals react with acids, the metal replaces the hydrogen in the acid. This produces a salt and releases hydrogen gas, which can be observed as bubbles.”
4. Combustion Reaction
- A combustion reaction is a chemical reaction in which a substance reacts rapidly with oxygen, usually releasing heat and often light.
General pattern
For a hydrocarbon:
Hydrocarbon + O₂ → CO₂ + H₂O + Energy
Example:
CH₄ + 2O₂ → CO₂ + 2H₂O + Energy
Methane reacts with oxygen and produces carbon dioxide, water, heat, and light.
“Combustion is basically burning. A substance reacts with oxygen and releases energy, usually in the form of heat and sometimes light.”
Easy way to remember:
🔥 Fuel + Oxygen → Energy
Real- life examples:
-burning wood
-cooking with a stove
Created using ChatSlide
This guide explores the fundamentals of chemical reactions, starting with definitions of reactants and products, and the concept of atom rearrangement. It categorizes core reaction patterns such as decomposition and acid reactions, emphasizing the importance of matching reactants to their types. Finally, it applies these patterns to real-life scenarios, like combustion, encouraging the balancing of equations and observation of physical evidence like fizzing and bubbling.