Calorie thermochemical

Measurements of energy are made in terms of absolute joules, but engineering practice has persistently retained the thermochemical calorie as the unit of energy. The two are related by the definition ... 

The only quantity considered here is the enthalpy of formation, A fH°, at 298.15 K. Data are given in units of kJmol-1. The conversion factor 1 thermochemical calorie = 4.1840 joules was used. 

Some Sl-derived units with special names are included in Table 2.2. The standard atmosphere may be used temporarily with SI units it is dehned to be equal to 1.01325 X 10 Pa. The thermochemical calorie is no longer recommended as a unit of energy, but it is defined in terms of an SI unit, joules, symbol J, as 4.184 J [4]. The unit of volume, liter, symbol L, is now defined as Idm. ... 

CALORIE (Thermochemical Calorie) (cal). A unit of heat. One calorie equals 4.1840 joules. (See foregoing note.)... 

An older unit of energy that is still common in physical chemistry circles is the calorie. One calorie was defined to be the amount of energy necessary to raise the temperature of 1 g of water from 14.5 to 15.5 °C. Today, one calorie (thermochemical calorie) is defined to be exactly 4.184 J. The ubiquitous food Calorie (note the capitalization) is a kilocalorie or 1000 cal. 

A piece of chocolate cake contains about 400 Calories. A nutritional Calorie is equal to 1000 calories (thermochemical calories). How many 8-in-high steps must a 180-lb man climb to expend the 400 Cal from the piece of cake See Exercise 15 for the formula for potential energy. 

Ibf) force to accelerate l(lbm) by 32.1740 (ft) s" atm = standard atmospheric pressure = 101 325 Pa (psia) E pounds force per square inch absolute pressure torr = pressure exerted by 1 mm mercury at 273.15 K (0°C) and standard gravity (cal) = thermochemical calorie (Btu) s international steam table British thermal unit (lb mole) s mass in pounds mass with numerical value equal to the molar mass (R) - absolute temperature in Rankines... 

Incidentally, the SI unit is not necessarily used in the thermal explosion theory. First, if joule is used instead of thermochemical calorie, the calculation of the becomes somewhat troublesome. Secondly, the thermal explosion is a phenomenon close to the human life in this regard, cubic centimeter is suitable for the case, while cubic meter is too big as a volume unit. And thirdly, the thermal explosion is a very slow phenomenon in this regard, minute is suitable for the case, while second is too short and too quick as a time unit. 

In all previous JANAF Thermochemical Tables, the standard-state pressure was one atmosphere (101 325 Pa) and the unit of energy was the thermochemical calorie (4.184 J). For this publication, the standard-state pressure is changed to one bar (100 000 Pa) and the energy unit to the joule. The values from previous JANAF tabulations have been converted as described below. This information is provided not only to make clear the correspondence between this publication and previous JANAF Thermochemical Tables but also to assist the reader in making comparisons with other tables. This information is the same as that provided in The NBS Tables of Chemical Thermodynamic Proper-... 

What units are associated with energy If you have forgotten, refer back to -Table-lvl—No - confiision-exists -with-respect-tO-the ioule.. but it is necessary tp be careful in specifying what type of calorie or British thermal unit (Btu) is under consideration (there are four or five common kinds). For example, the type of calorie that is found in older tables of thermochemical properties of substances is the thermochemical calorie (equal to 4.184 J), whereas a second type of calorie is the International Steam Table (I.T.) calorie (equal to 4.1867 J). A kcal in nutrition is just called a calorie that is, a hamburger containing 500 calories really contains 500 kcal. 

Calories should not be used, because there are different calories cal, (thermochemical calorie, 4.184 J), cal,., (international calorie, 4.1868 J), and the cal, (15 °C calorie, approximately 4.1855 J). It is often not clear which conversion was used in a given context. Many more examples can be found in section 7.2 of [1]. 

Two calories are defined. The thermochemical calorie (cal), used in chemistry, is defined by... 

The Fifth International Conference on the Properties of Steam (London, July 1956) defined the International Table calorie as 4.1868 J. Therefore the exact conversion factor for the International Table Btu is 1.055 055 852 62 kj. Note that the notation for the International Table used in this listing is subscript IT . Similarily, the notation for thermochemical is subscript th. Further, the thermochemical Btu, Btu, is based on the thermochemical calorie, caL, where caL = 4.184 ] exactly. 

Calorie (cal) - A non-SI unit of energy, originally defined as the heat required to raise the temperature of 1 g of water by 1 °C. Several calories of slightly different values have been used. The thermochemical calorie is now defined as 4.184 J. 

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