chemical equation: Basic Notation Used in Equations
The chemical equation 2H 2+O 2→2H 2O represents the reaction of hydrogen and oxygen to form water. The arrow points in the direction of the reaction—from the reactants (substances that react) toward the product or products. In this case the reactants are hydrogen (written H 2 because each molecule consists of two atoms of hydrogen) and oxygen (written O 2 because each molecule consists of two atoms of oxygen) and the product is water. The coefficient 2 before the H 2 indicates that two molecules of hydrogen take part in the reaction, and the 2 before the H 2O indicates that two molecules of water are produced. When no number is written, as in front of the O 2, a one is assumed; one molecule of oxygen takes part in the reaction. The equation shows that two molecules of hydrogen react with one molecule of oxygen to form two molecules of water. Because of the relationship between molecules and the mole , the equation also shows that two moles of hydrogen react with one mole of oxygen to form two moles of water. The same sort of relationship holds with the gram- formula weight .
- Methodology for Writing an Equation
- Additional Symbols Used in Chemical Equations
- Basic Notation Used in Equations
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