ABSTRACT
We defined chemistry in Chapter 1 as the study of the composition, structure, and properties of matter and the changes that matter undergoes. As our study of chemistry has unfolded in Chapters 1-7, we have learned that a great deal of symbolism (element symbols, formulas of compounds, chemical equations, etc.) is used to describe chemical composition, structure, properties, and changes. We have also learned that some aspects of chemistry, particularly aspects of structure, can be very abstract, requiring us to think in terms of the extremely small invisible particles called atoms, molecules, and ions, and even the smaller subatomic particles called protons, neutrons, and electrons. The special language of chemists and chemistry technicians, however, is certainly not limited to the abstract or to very small quantities. In this chapter, we move from the realm of the abstract and unseen to the realm of observable and measurable realities. It is time to apply our symbolism and our knowledge to quantities of matter that are observable and measurable in the laboratory and to the very large quantities of matter that are generated and consumed every day in the chemical industry. The expression, measurement, and calculation of quantities of matter in compounds and in reactions is called stoichiometry.
