Calorie

A calorie (cal) is a unit of thermal energy, equivalent to about 4.185 J.

Related Topics:
Unit - Thermal energy

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By definition, one calorie is the energy needed to increase the temperature of 1 g of water by 1 °C at 15 °C under normal atmospheric pressure (76 cmHg). In nutrition, it is used to quantify the energy of food and the defining quantity of water is 1 kilogram, making the "food calorie" 1000 times as large as the other calorie. Hence, 1 calorie (nutrition) = 1 kcal = 1000 cal, and it is also called the large calorie.

Related Topics:
G - Normal atmospheric pressure - Nutrition - Energy of food - Kilogram

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The calorie is not an SI unit where the joule is the only unit of energy. The kilocalorie is frequently used in chemistry because it is a convenient measure of molar free energy: for example, 1.4 kcal/mol engenders a change in equilibrium by a factor of 10.

Related Topics:
SI unit - Joule - Chemistry - Free energy

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