4What is a Chemical Reaction? A process in which new substances with new chemical and/or physical properties are formed.A burning piece of paper (Chemical Reaction):paper ashes, water vapor, and carbon dioxideDissolving salt in water (No Reaction):Salt Water → Salt Water
5Parts of a Chemical Equation Na+ Cl → NaClsodiumandchlorineyieldssodium chlorideReactantsThe substances that you start with. In this case:Sodium and Chlorine“Yields”This arrow tells you that the reactants become the products through a chemical reaction.ProductsThe substances you end with. In this case:Sodium Chloride
7Types of Chemical Reactions Type 1: Synthesis In a synthesis reaction, two (or more) simple substances form a more complex substance.Synthesis: Two Become OneA + B → AB
8Synthesis Example Na + Cl → NaCl sodium and chlorine yields sodium chloride
9Types of Chemical Reactions Type 2: Decomposition In a decomposition reaction, a complex substance is broken down into two (or more) simpler substances.Decomposition: One Becomes TwoAB → A + B
10Decomposition Example H2O2 → H2O + O2hydrogen peroxide yields water and oxygen
11Types of Chemical Reactions Type 3: Single Replacement Reaction In a single replacement reaction, a single element replaces another element in a compound.Single Replacement: Start with one compound, end with a different compound.
13Single Replacement Example Zn HCl → H2 + ZnCl2zinc and hydrochloric acid yields hydrogen and zinc chloride
14Types of Chemical Reactions Type 4: Double Replacement Reaction In a double replacement reaction, elements from two compounds switch places and form two new compounds.Double Replacement: Start with two compounds, end with two different compounds.