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Chemistry LibreTexts

5: Chemical Reactions and Quantities

  • Page ID
    290502
    • 5.1: Prelude to Introduction to Chemical Reactions
      Although yeast has been used for thousands of years, its true nature has been known only for the last two centuries. Yeasts are single-celled fungi. About 1,000 species are recognized, but the most common species is Saccharomyces cerevisiae, which is used in bread making. Other species are used for the fermentation of alcoholic beverages. Some species can cause infections in humans.
    • 5.2: The Law of Conservation of Matter
      One scientific law that provides the foundation for understanding in chemistry is the law of conservation of matter. It states that in any given system that is closed to the transfer of matter (in and out), the amount of matter in the system stays constant. A concise way of expressing this law is to say that the amount of matter in a system is conserved. The amount of matter in a closed system is conserved.
    • 5.3: Chemical Equations
      Chemical reactions are represented by chemical equations that list reactants and products. Proper chemical equations are balanced; the same number of each element’s atoms appears on each side of the equation.
    • 5.4: Quantitative Relationships Based on Chemical Equations
      A balanced chemical equation not only describes some of the chemical properties of substances—by showing us what substances react with what other substances to make what products—but also shows numerical relationships between the reactants and the products. The study of these numerical relationships is called stoichiometry.  A balanced chemical equation gives the ratios in which molecules of substances react and are produced in a chemical reaction.
    • 5.5: Mole-Mole Relationships in Chemical Reactions
      The balanced chemical reaction can be used to determine molar relationships between substances.
    • 5.6: Mole-Mass and Mass-Mass Problems
      A balanced chemical equation can be used to relate masses or moles of different substances in a reaction.

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