Calorie, defined

Heat is measured in term.s of the calorie, defined as the amount of heat necessary to raise the temperature of 1 gram of water at a pressure of 1 atmosphere firom 15 to 16 °C. This unit is sometimes called the small calorie, or gram calorie, to distinguish it from the large calorie, or kilocalorie, equal to 1000 small calories, which is used in nutritional studies. In mechanical engineering practice in the United States and the United Kingdom, heat is measured in British thermal units (Btu). One Btu is the quantity of heat required to raise the temperature of 1 pound of water 1 ° F and is equal to 252 calories. 

Calorie Defined as exactly 4.184 joules. Originally defined as the amount of heat required to raise the temperature of one gram of water from 14.5°C to 15.5°C. 

The calorie defined by the U.S. National Bureau of Standards as 4.18400 J and used in thermochemical data tables. 

How is the calorie defined How does a Calorie differ from a calorie How is the joule related to the calorie ... 

A more common unit of energy in the cgs system is the calorie, defined as the energy necessary to raise the temperature of 1 g of water by 1 K. The following conversion factors are required to convert to ergs and Joules ... 

Prior to the now almost universal adoption of the SI system of units, the unit of heat was defined as the quantity of heat required to raise the temperature of unit mass of water by one degree. This heat quantity is designated the calorie in the cgs system and the kilocalorie in the mks system, and in both cases temperature is expressed in degrees Celsius (Centigrade). As the specific heat capacity is a function of temperature, it has been necessary to set a datum temperature which is chosen as 298 K or 25°C. 

You have now defined lieat" itself as the amount of energy required to rjiise 1 cc. of water by one degree eis one calorie. However, the temperature at... 

ALL CHANGES IN PHASE involve a release or absorption of calories. One reason for this is that each solid has its own heat capacity. That is, there is a characteristic heat content for each material which depends upon the atoms composing the solid, the nature of the lattice vibrations within it, and its structure. The total heat content, or enthalpy, of each solid is defined by ... 

The amount of heat released by the complete combustion of one mole of a substance is defined as the heat of combustion, AAVcomb The amount of heat released may be measured in calories (cal) or in joules (J). A calorie is the amount of heat needed to raise the temperature of one gram of water one degree Celsius. The SI unit of heat is the joule. One joule is equal to 4.184 calories. 

The most common units of energy used in the study of thermodynamics are the joule and the calorie. The joule (J) is defined as ... 

The calorie was originally defined as the amount of energy needed to raise the temperature of 1 g of water 1°C. Now it is defined in terms of its relationship to the joule ... 

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. ... 

There is essentially no difference between work and energy. Both are measured in joule (J = 1 N m). An outdated unit is the calorie (1 cal = 4.187 J). Energy is defined as the ability of a system to perform work. There are many different forms of energy—e.g., mechanical, chemical, and radiation energy. 

For chemical reactions and phase transformations, the energy absorbed or liberated is measured as heat. The principal unit for reporting heat is the calorie, which is defined as the energy needed to raise the temperature of 1 gram of water at l4.5° C by a single degree. The term kilocalorie refers to 1,000 calories. Another unit of energy is the joule (rhymes with school), which is equal to 0.239 calories. Conversely, a calorie is 4.184 joules. The translation of calories to joules, or kilocalories to kilojoules, is so common in chemical calculations that you should memorize the conversion factors. 

Another important characteristic of an explosive which might influence its force is the energy, which is defined as the heat (in calories per unit weight) produced on detonation or explosion. It may be either calculated or determined experimentally using a small, thick-walled calorimetric bomb. 

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