Common Functions and Chemical Applications

The energies associated with chemical processes are inconveniently small when expressed in Joules. For example, the dissociation energy for the bond in the H2 molecule is 7.17 x 10-19 J. It is thus more common to write the energy associated with breaking one mole of such bonds (432 kJ mol-1). Another convenient energy unit is the electron volt (eV), which (as the name implies) is the energy picked up by an electron when it is moved across a potential of one volt. We will discuss this more in Chapters 3 and 5. 

However, the fraction of deuterium can vary in naturally occurring samples, because isotopic substitution can slightly change chemical properties. Normal water (H2O) boils at 100°C (at 1 atm pressure) and freezes at 0°C heavy water (D2O) boils at 101.42°C and freezes at 3.82°C. 

The task of reconciling experimental measurements in many different laboratories to produce the best possible set of fundamental physical constants is assigned to CODATA (the Committee on Data for Science and Technology), established in 1966 by the International Council of Scientific Unions. Roughly every ten years this group releases a new set of constants. Appendix A presents the 1998 values. Each value also has associated error bars, which we will explain in more detail in Chapter 4. 

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T2l COMMON FUNCTIONS AND CHEMICAL APPLICATIONS 1.2.1 Definition of Functions and Inverse Functions... 

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