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Reactions: Prediction and Synthesis
Two important questions asked in the study of chemistry are (1) "Will a reaction take place when you mix reactants A and B?" and (2) "How do you
prepare a given compound, X?"
The first question concerns prediction, and the second concerns synthesis.
They are related. In the first you are given the reactants (the lefthand side of the
equation) and are asked to predict the products. In the second you are given a
product (the righthand side of the equation) and are asked to suggest suitable
reactants. For synthesis you must use a reaction that is predicted to "go"; the
products of a reaction that is predicted to "go" actually correspond to a chemical synthesis. This chapter gives an organized approach to answering these
questions, including writing the chemical equations for the reactions involved.
PREDICTION
Fundamentally, a reaction "goes" if it is accompanied by a decrease in free
energy (AG is negative), as discussed in Chapter 17. The experimental conditions that lead to the fulfillment of this principle are summarized in the following
statement.