Calories 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. 

A calorie is defined as the heat energy needed to raise the temperature of... 

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. 

The heat developed in a circuit by an electric current of I - 1 ampere flowing through a resistance of R, - 1 ohm (across a potential difference of V, - 1 volt) for a time t — 1 second is defined to be 1 ioule. One calorie is defined as equal to 4.1840 joules and corresponds very closely to the heat required to raise the temperature of 1 g of pure water from 14.5 to 15.5 C. More generally, the heat developed by current flow in a circuit is specified by... 

The heat transfer was originally measured in units of calories, where one calorie was defined as the quantity of energy required to raise one gram of pure water from 14.5 to 15.5 °C at one atmosphere. This definition has been supplanted by the introduction of the joule, which represents the energy specified by the conversion factor 1 cal = 4.184 joules. One joule is also equivalent to the energy developed in a circuit by an electric current of one ampere flowing through a resistance of one ohm (driven by a potential difference of one volt) in one second. 

For the values of the principal physical constants see R. T. Birge, Phys. Soc. Rep. Prog. Phys., 8, 90 (1941). Note also that in conformity with the recommendation of the International Union of Physics (S. G. 48-6, 1948) the calorie is defined as 4 1840 abs. joules. The above table has been revised in accordance with the latest recommendations of the Bureau of Standards, Tables of Selected Values of Chemical Thermodynamic Properties (Washington, 1947). 

Because heat, like work, is a form in which energy is transferred, the appropriate unit for it is also the joule. Historically, however, the connections among work, heat, and energy were not appreciated until the middle of the 19th century, by which time a separate unit for heat, the calorie, was already well established. One calorie was defined as the amount of heat required to increase the temperature of 1 g water from 14.5°C to 15.5°C (or, in other words, the specific heat capacity of water, Cg, at 15°C was defined as 1.00 cal g )-... 

In order to convert the results obtained by the electrical heating method into calories, it is necessary to know the relationship between joules and calories. That there is such an exact connection is really an aspect of the first law of thermodynamics ( 6a), which will be tacitly assumed for the present. Because of a slight uncertainty, of about two parts in 10,000, concerning the relationship between the standard (K5 ) calorie, as defined in 3d, and the int. joule ( 3b), a defined calorie,... 

One calorie is defined as exactly 4.184 J. The so-called large calorie, used to indicate the energy content of foods, is really one kilocalorie, that is, 1000 calories. We shall do most calculations in joules. 

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. 

One calorie is defined as the amount of heat energy required to increase the temperature of 1 gram of water 1°C. 

Energy absorbed or liberated in chemical reactions is most often in the form of heat energy. Heat energy may be represented in units of calories or joules 1 calorie (cal) = 4.18 joules (J). One calorie is defined as the amount of heat energy required to change the temperature of 1 gram of water 1°C. 

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

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

In the metric system the calorie is defined as the amount of energy (heat) required to raise the temperature of one gram of water by one Celsius degree. The "calorie" with which you are probably familiar is used to measure the energy content of food and is actually a kilocalorie (1000 calories), written with a capital C (Calorie) to distinguish it from the calorie used in chemistry. The joule (an SI unit) can be most conveniently defined in terms of the calorie ... 

Heat is quantitatively defined by measurement with a calorimeter, that is, by the temperature increment produced in its transfer to a standard body in the course of a change of state of the system. The unit of heat is the calorie the mean gram-calorie is one one-hundredth of the heat absorbed by one gram of liquid water under a pressure of one atmosphere on raising its temperature from 0 to 100°C. The 15° gram-calorie is defined as the heat required to raise the temperature of one gram of water from 14.5 to 15.5°C. The ratio of the latter to the former is 1.00024. 

Throughout this survey the substance is parahydrogen. Pressures P are given in atm, temperatures, T K, are based on the NBS 1955 low-temperature scale and densities, p = Ifv, are in g-moles/cm P]. One calorie is defined as 4.1840 abs joules, or 41.2929 cc-atm. Molecular weight used for hydrogen is 2.01572 g/mole. 

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 ... 

As we explained the Btu (British thermal unit) in Chapter 11, one Btu is formally defined as the amount of thermal energy needed to raise the temperature of 1 lb of water by 1°R The calorie is defined as the amount of heat required to raise the temperature of 1 g of water by 1°C. And as you may also recall from our discussion in Chapter 11, in SI units no distinction is made between the units of thermal energy and mechanical eneigy, and therefore the units of thermal energy are defined in terms of fundamental dimensions of mass, length, and time. In the SI system of units, the joule is the unit of energy and is defined as... 

The joule has become the most widely accepted unit for energy, and so these other units are now defined in terms of it. A calorie is defined as 4.184 J, and a Btu is defined as 1055 J. A source of frequent confusion in comparing energy units is that the Calorie reported for foods is actually a kilocalorie. (The food Calorie should be written with an uppercase C. ) Thus, 1 Calorie is actually equivalent to 4184 J, or 4.184 kJ. 

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