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It is defined as one kilocalorie of energy (1000 thermochemical gram calories) per one mole of substance. The unit symbol is written kcal/mol or kcal⋅mol −1. As typically measured, one kcal/mol represents a temperature increase of one degree Celsius in one liter of water (with a mass of 1 kg) resulting from the reaction of one mole of reagents.
The precise equivalence between calories and joules has varied over the years, but in thermochemistry and nutrition it is now generally assumed that one (small) calorie (thermochemical calorie) is equal to exactly 4.184 J, and therefore one kilocalorie (one large calorie) is 4184 J or 4.184 kJ.
A moderate energy density would be 1.6 to 3 calories per gram (7–13 kJ/g); salmon, lean meat, and bread would fall in this category. Foods with high energy density have more than three calories per gram (>13 kJ/g) and include crackers, cheese, chocolate, nuts, [10] and fried foods like potato or tortilla chips.
The calorie is defined as the amount of thermal energy necessary to raise the temperature of one gram of water by 1 Celsius degree, from a temperature of 14.5 °C, at a pressure of 1 atm. For thermochemistry a calorie of 4.184 J is used, but other calories have also been defined, such as the International Steam Table calorie of 4.1868 J.
the small calorie (gram-calorie, cal) is 4.184 J exactly. It was originally defined so that the specific heat capacity of liquid water would be 1 cal/(°C⋅g). The grand calorie (kilocalorie, kilogram-calorie, food calorie, kcal, Cal) is 1000 small calories, 4184 J exactly. It was defined so that the specific heat capacity of water would be 1 ...
Macronutrients are defined as a class of chemical compounds which humans consume in relatively large quantities compared to vitamins and minerals which provide humans with energy. Fat has a food energy content of 38 kilojoules per gram (9 kilocalories per gram) proteins and carbohydrates 17 kJ/g (4 kcal/g). [2]
The "grand calorie" (also "kilocalorie", "kilogram-calorie", or "food calorie"; "kcal" or "Cal") is 1000 small calories, that is, 4184 J, exactly. When heat is measured in these units, the unit of specific heat is usually 1 cal/(°C⋅mol) ("small calorie") = 4.184 J⋅K −1 ⋅mol −1 1 kcal/(°C⋅mol) ("large calorie") = 4184 J⋅K −1 ...
[1] [2] For example, the Gibbs free energy of a compound in the area of thermochemistry is often quantified in units of kilojoules per mole (symbol: kJ·mol −1 or kJ/mol), with 1 kilojoule = 1000 joules. [3] Physical quantities measured in J·mol −1 usually describe quantities of energy transferred during phase transformations or chemical ...