Overview
This lecture covers the classification of chemical reactions into five main types, providing examples and key patterns for each.
Types of Chemical Reactions
- Chemical reactions are categorized into synthesis, decomposition, single replacement, double replacement, and combustion reactions.
- Each type has a generic pattern or sample equation helpful for identification.
Synthesis Reactions
- Synthesis (or combination) reactions involve two simple substances forming one complex product.
- Example: Magnesium + Oxygen → Magnesium Oxide.
Decomposition Reactions
- Decomposition reactions involve one compound breaking down into simpler substances.
- Example: Magnesium Chloride → Magnesium + Chlorine gas.
- Decomposition can produce elements or simpler compounds (not just pure elements).
Single Replacement Reactions
- Single replacement (or single displacement) occurs when one element replaces another in a compound.
- Example: Magnesium + Aluminum Chloride → Aluminum + Magnesium Chloride.
- Example: Zinc + Hydrochloric Acid → Zinc Chloride + Hydrogen gas.
Double Replacement Reactions
- Double replacement reactions involve two compounds exchanging partners to form two new compounds.
- Example: Silver Nitrate + Sodium Chloride → Silver Chloride + Sodium Nitrate.
- Example: Sodium Chloride + Sulfuric Acid → Sodium Sulfate + Hydrochloric Acid.
Combustion Reactions
- Combustion reactions occur when a compound reacts with oxygen to produce carbon dioxide and water.
- Example: Octane + Oxygen → Water + Carbon Dioxide.
- Example: Glucose + Oxygen → Carbon Dioxide + Water.
- Combustion can involve substances containing carbon, hydrogen, and sometimes oxygen.
Key Terms & Definitions
- Synthesis Reaction — two or more simple substances combine to form a more complex substance.
- Decomposition Reaction — a complex substance breaks down into two or more simpler substances.
- Single Replacement Reaction — an element replaces another in a compound.
- Double Replacement Reaction — two compounds switch partners to form two new compounds.
- Combustion Reaction — a substance reacts with oxygen, producing CO₂ and H₂O.
Action Items / Next Steps
- Memorize the generic patterns and example equations for each reaction type.
- Practice classifying reactions without using a reference chart.