Chapter 5- 2: Writing Chemical Equations
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Transcript of Chapter 5- 2: Writing Chemical Equations
Chapter 5- 2: Writing Chemical Equations
I. Understanding Chemical Equations
A. Chemical equations are a short way to writechemical reactions1. 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
A. 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:
1. synthesis reactions2. decomposition reactions3. replacement reactions
1. Synthesis Reaction:a. reaction in which two or more substances
combine to form a single compound.
For example: Na +Cl NaCl
2. Decomposition reactiona. 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 through electrolysis.
3. Single replacement reactiona. when one element replaces another in a
compound.Example: Zn +2HCl ZnCl2+ H2
Single replacement reaction:
4. Double replacement reaction a. reaction in which ions in two compounds switch places.Example: NaCl +AgF NaF +AgCl