Factors for Energy Units

In this article both unsensitized and mercury vapor sensitized reactions are discussed. The plan has been to proceed from the chemically simplest system, oxygen molecule, to the chemically most complex, ozone plus hydrogen peroxide. Unless otherwise stated, thermochemical values have been taken from compilations of the National Bureau of Standards (68) and are reported in kcal. for the reaction represented in mole amounts. Conversion factors for energy units, spectroscopic notation, and unless noted, spectroscopically based values have been taken from... 

Tables for fundamental constants, conversion factors for energy units and entropy gases are presented in Chapter 8.

Conversion factors for energy units (from NBS Tables)... 

Table 4-19 shows data on energy consumption for different crops, both on a per hectare and per output unit scale. The determining factor for energy consumption of a specific crop is its cropping management, which includes tillage intensity, manuring and weed control. 

Appendix A gives an extensive table of conversion factors for energy as well as for other units. 

Section 7.1 gives examples illustrating the use of quantity calculus for converting the values of physical quantities between different units. The table in section 7.2 lists a variety of non-SI units used in chemistry, with the conversion factors to the corresponding SI units. Conversion factors for energy and energy-related units (wavenumber, frequency, temperature and molar energy), and for pressure units, are also presented in tables inside the back cover. 

Various units are used for expressing pressures (see Chapter 1, Footnote 8). A pressure of one standard atmosphere, or 0.1013 MPa, can support a column of mercury 760 mm high or a column of water 10.35 m high. As indicated in Chapter 1, the SI unit for pressure is the pascal (Pa), which is 1 N m-2 an SI quantity of convenient size for hydrostatic pressures in plants is often the MPa (1 MPa = 10 bar = 9.87 atm). (An extensive list of conversion factors for pressure units is given in Appendix II, which also includes values for related quantities such as RT.) Pressure is force per unit area and so is dimensionally the same as energy per unit volume (e.g., 1 Pa = 1 N m-2 = 1J m-3). Vw has the units of m3 mol-1, so VWP and hence /aw can be expressed in J mol-1. 

Conversion factors for energy-related units. 1973 CODATA constants... 

Power is the rate at which energy is transferred, and therefore it has dimensions of [ML2/P]. One watt (W) is defined as 1 J/sec. Other common units are horsepower and Btu/hr. (Curiously, the metric cheval-vapeur is equivalent to only 735 W, slightly less than the U.S./British horsepower of 746 W.) See Table A-9 for interconversion factors for these units. 

It is often necessary to convert the adopted value of a fundamental constant to another (SI or non-SI) unit. Useful conversion factors for energy equivalent quantities can be derived using the following relations ... 

Each equality for energy units can be written as two conversion factors ... 

Table 1.2. Conversion Factors for Energy and Mass Units 1 u = 1.6605656 X lO kg...

Fig. 4. Free-energy storage per monomer unit against monomer-flow field interaction energy a = exp (—AEg/kuT) with AEg = relative energy of the gauche with respect to the trans conformation P = exp (- AUfri( 1/kBT) = Boltzmann factor for the monomer-flow field interaction energy (AUfrii.t)...

The use of non-SI units is strongly discouraged. For these units there often do not exist standards, and for historical reasons the same denomination may mean sundry units. For example, it is common practice in theoretical chemistry to state energy values in kilocalories. However, to convert a calorie to the SI unit Joule, there exist different conversion factors ... 

The process is first divided into a number of units which are assessed individually. The dominant material for each unit is then selected and its material factor determined. The material factor in the Mond index is a function of the energy content per unit weight (the heat of combustion). 

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