1. Chemical Reactions and Equations
Chapter 12 - Lesson 2
Types of Chemical Reactions

2. How can you recognize the type of chemical reaction by the number or type of reactants and products?
What are the different types of chemical reactions?
Essential Questions
Lesson 2

3. Big Ideas
Classify Chemical Reactions by Substances
It is human nature to want to classify items into categories to help understand their composition and how the items relate to one another. In this lesson, chemical reactions are classified into four main categories: synthesis, decomposition, replacement reactions, and combustion. Within replacement reactions, there are single and double replacement reactions. This category is based on how the atoms of the elements change from reactants to products. For example, in synthesis, two or more substances combine and form a new substance; in other words, the atoms in the substances (reactants) break apart and then combine in a new way and form new substances (products).

4. Synthesis - chemical reaction in which two or more substances combine and form one compound.
Decomposition - chemical reaction in which one compound breaks down and forms two or more substances.
Single Replacement - describes a reaction in which one element replaces another element in a compound.
Double Replacement - describes a reaction in which the negative ions in two compounds switch places, forming two new compounds.
Combustion - chemical reaction in which a substance combines with oxygen and releases energy.
Vocabulary
Lesson 2