Calorie International Table

CALORIE (International Table) (cal/x). A unit of heat. One International Table calorie equals 4.1 S68 joules. (The 9th Conference Generale des Poids et Mesures adopted the joule as the unit of heat.)... 

The Fifth International Conference on the Properties of Steam (London, uly 1956) defined the International Table calorie as 4.1868 J. Therefore die exact conversion factor for die International Table Btu is 1.055 055 852 62 kJ. Note diat the notation for die International Table used in diis listing is subscript IT. Similarily, the notation for diermochemical is subscript di. Furdier, die diermochemical Btu, Btu j, is based on die diermochemical calorie, calu, where cal j = 4.184 J exactly. 

A small point to note in using Steam Tables as well as program steam is that these sources use the International Table calorie, which is defined as 4.1868 joules. Physical chemistry sources generally use the thermochemical calorie, which is 4.184 joules. This makes it difficult to be completely consistent when using calories for aqueous solutions, and is a good reason for using the SI system of units. 

This is the thermochemical calorie, used in most of physical chemistry. The International Table calorie used in Steam Tables is 4.1868 J (see page 388). 

Calorie (thermochemical calorie) cal 1 cal = 4.1840 J (see note for International Table calorie). 

The mean or thermochemical calorie (calxH) is defined as 4.184 joules. The international table calorie (calu) is defined as 4.1868 joules. Formerly the mean calorie was defined as one hundredth of the heat needed to raise one gram of water from 0°C to 100°C, and the 15°C calorie as the heat needed to raise it from 14.5°C to 15.5°C. 

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