1.3. METHODS OF EXPRESSING TEMPERATURES AND COMPOSITIONS

1.3A. Temperature

There are two temperature scales in common use in the chemical and biological industries. These are degrees Fahrenheit (abbreviated °F) and Celsius (°C). It is often necessary to convert from one scale to the other. Both use the freezing point and boiling point of water at 1 atmosphere pressure as base points. Often temperatures are expressed as absolute degrees K (SI standard) or degrees Rankine (°R) instead of °C or °F. Table 1.3-1 shows the equivalences of the four temperature scales.

Table 1.3-1. Temperature Scales and Equivalents
 CentigradeFahrenheitKelvinRankineCelsius
Boiling water100°C212°F373.15 K671.67°R100°C
Melting ice0°C32°F273.15 K491.67°R0°C
Absolute zero

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