Collections:Texts:Chemistry:Chapter 2 - Atoms, Molecules, and Chemical Reactions
From ChemEd Collaborative
ATOMS, MOLECULES AND CHEMICAL REACTIONS
2.1 Macroscopic Properties and Microscopic Models
2.2 Historical Development of the Atomic Theory
2.4 Macroscopic and Microscopic Views of a Chemical Reaction
2.7 The Amount of Substance: Moles
2.10 Balancing Chemical Equations
In Chap. 1 we described two very important things that chemists (and scientists in general) do. They make quantitative measurements, and they communicate the results of such experiments as clearly and unambiguously as possible. In this chapter we will deal with another important activity of chemists-the use of their imaginations to devise theories or models to interpret their observations and measurements. Such theories or models are useful in suggesting new observations or experiments which yield additional data. They also serve to summarize existing information and aid in its recall.
The atomic theory, first proposed in modern form by John Dalton, is extremely important to chemists. It interprets observations of the every-day world in terms of particles called atoms and molecules. Macroscopic events—those which humans can observe or experience with their unaided senses—are interpreted by means of microscopic objects—those so small that a special instrument or apparatus must be used to detect them. (Perhaps the term submicroscopic really ought to be used, because most atoms and molecules are much too small to be seen even under a microscope.) In any event, chemists continually try to explain the macroscopic world in microscopic terms.
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