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Chapter 5- 2: Writing Chemical Equations. I. Understanding Chemical Equations. A. Chemical equations are a short way to write chemical reactions 1. uses symbols instead of words. Examples: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2. or 2H 2 + O 2 2H 2 O.
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I. Understanding Chemical Equations A. Chemical equations are ashort way to write chemical reactions 1. uses symbols instead of words. Examples: 6CO2 + 6H2O C6H12O6 + 6O2 or 2H2 + O2 2H2O
B. Structure of an Equation 1. 2. 3. 4.
II. Conservation of Mass • mass of the reactants must equal mass of products. • 1. beginning mass = ending mass
III. Classifying Chemical Reactions • A. Three (3) types of chemical reactions: • synthesis reactions • decomposition reactions • replacement reactions
Synthesis Reaction: • a. reaction in which two or more substances • combine to form a single compound. • For example: Na +Cl NaCl
Decomposition reaction • a. reaction in which a single compound breaks • down to form two ore more simpler • substances. • For example: H2O2 H2O + O2
Water can be decomposed into the elements hydrogen and oxygen throughelectrolysis.
Single replacement reaction • a. when one element replaces another in a • compound. • Example: Zn +2HCl ZnCl2+ H2
4. Double replacement reaction a. reaction in which ions in two compounds switch places. Example: NaCl +AgF NaF +AgCl