What Is a Unit of Expression of Energy Equal to 1,000 Calories?

Unit of measurement of energy used in diet

A 710-millilitre (24 US fl oz) energy drinkable with 330 kilocalories

The calorie is a unit of energy.^{[1] [2]} For historical reasons, two master definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the corporeality of rut needed to raise the temperature of one kilogram of water by one degree Celsius (or ane kelvin).^{[1] [3]} The small-scale calorie or gram calorie was defined as the amount of heat needed to crusade the same increase in 1 gram of water.^{[3] [4] [five] [i]} Thus, ane large calorie is equal to thou pocket-sized calories.

In diet and nutrient science, the term calorie and the symbol cal almost always refers to the large unit. It is generally used in publications and package labels to express the energy value of foods in per serving or per weight, recommended dietary caloric intake,^{[6] [7]} metabolic rates, etc. Some authors recommend the spelling Calorie and the symbol Cal (both with a capital C) to avoid confusion;^[8] however, this convention is often ignored.^{[half-dozen] [seven] [eight]}

In physics and chemistry the word calorie and the symbol cal oftentimes refer to the small unit; the large ane existence called kilocalorie, with symbol kcal. However, this unit is not officially part of the metric system (SI), and is regarded as obsolete,^[2] having been replaced in many uses by the SI unit of energy, the joule (J).^[9]

The precise equivalence betwixt calories and joules has varied over the years, only in thermochemistry and nutrition it is now by and large causeless that one (modest) calorie is equal to exactly 4.184 J, and therefore i kilocalorie (i large calorie) is 4184 J, or 4.184 kJ.^{[ten] [eleven]}

History [edit]

The term "calorie" was kickoff introduced by Nicolas Clément, equally a unit of measurement of heat free energy, in lectures on experimental calorimetry during the years 1819–1824.^[12] This was the "large" calorie.^{[2] [13] [14]} The term (written with lowercase "c") entered French and English dictionaries between 1841 and 1867. It comes from Latin calor 'estrus'.

The aforementioned term was used for the "small" unit by Pierre Antoine Favre (Chemist) and Johann T. Silbermann (Physicist) in 1852. This unit was used by U.S. medico Joseph Howard Raymond, in his classic 1894 textbook A Transmission of Homo Physiology.^[fifteen] He proposed calling the "large" unit "kilocalorie", but the term didn't catch on until some years afterwards.

In 1879, Marcellin Berthelot distinguished between gram-calorie and kilogram-calorie, and proposed using "Calorie", with upper-case letter "C", for the large unit.^[2] This usage was adopted past Wilbur Olin Atwater, a professor at Wesleyan University, in 1887, in an influential article on the energy content of food.^{[two] [13]}

The small calorie (cal) was recognized as a unit of the cm-yard-s system (cgs) in 1896,^{[two] [14]} alongside the already-existing cgs unit of energy, the erg (showtime suggested by Clausius in 1864, under the name ergon, and officially adopted in 1882).

Already in 1928 there were serious complaints almost the possible confusion arising from the two main definitions of the calorie and whether the notion of using the uppercase letter of the alphabet to distinguish them was sound.^[16]

The pocket-sized calorie was originally part of the metric organisation (SI),^[x] but it was officially deprecated past the ninth General Conference on Weights and Measures in 1948.^[17] in favor of the joule.^[9]

The alternate spelling calory is primitive.^{[ citation needed ]}

Definitions [edit]

The "modest" calorie is broadly defined as the amount of energy needed to increase the temperature of one gram of water by 1 °C (or ane K, which is the aforementioned increment).^{[iv] [5]} The amount depends on the atmospheric pressure and the starting temperature, and different choices of these parameters take resulted in several different precise definitions of the unit of measurement.

Name	Symbol	Conversions	Definition and notes
Thermochemical calorie	calthursday	≡ 4.184 J ≈ 0.003964 BTU ≈ 1.162×10−half dozen kW⋅h ≈ 2.611×1019 eV	The amount of free energy equal to exactly four.184 J (Joules) and 1 kJ = 0.239 kcal.[18] [19] [twenty] [11] (a).
iv °C calorie	cal4	≈ four.204 J ≈ 0.003985 BTU ≈ ane.168×x−half dozen kW⋅h ≈ 2.624×xxix eV	The corporeality of free energy required to warm one gram of air-free h2o from 3.v to 4.5 °C at standard atmospheric pressure. (c)
15 °C calorie	calxv	≈ 4.1855 J ≈ 0.0039671 BTU ≈ 1.1626×10−vi kW⋅h ≈ 2.6124×10xix eV	The corporeality of energy required to warm one gram of air-free h2o from 14.5 to xv.5 °C at standard atmospheric pressure. (c) Experimental values of this calorie ranged from four.1852 to 4.1858 J. The CIPM in 1950 published a mean experimental value of four.1855 J, noting an uncertainty of 0.0005 J.[18]
20 °C calorie	cal20	≈ 4.182 J ≈ 0.003964 BTU ≈ i.162×10−6 kW⋅h ≈ 2.610×xnineteen eV	The amount of free energy required to warm one gram of air-free h2o from 19.5 to xx.5 °C at standard atmospheric pressure. (c)
Mean calorie	calmean	≈ iv.190 J ≈ 0.003971 BTU ≈ 1.164×10−six kW⋅h ≈ 2.615×ten19 eV	Divers equally 1⁄100 of the amount of energy required to warm one gram of air-free water from 0 to 100 °C at standard atmospheric pressure. (c)
International Steam Table calorie (1929)		≈ iv.1868 J ≈ 0.0039683 BTU ≈ 1.1630×x−six kW⋅h ≈ ii.6132×10xix eV	Divers as 1⁄860 "international" watt hours = 180⁄43 "international" joules exactly. (b)
International Steam Tabular array calorie (1956)	calIt	≡ iv.1868 J ≈ 0.0039683 BTU = one.1630×10−half-dozen kW⋅h ≈ 2.6132×1019 eV	Defined as 1.163 mW⋅h = 4.1868 J exactly. This definition was adopted past the 5th International Briefing on Properties of Steam (London, July 1956).[18]

(a) The 'Thermochemical calorie' was defined by Rossini simply as 4.1833 international joules in social club to avoid the difficulties associated with uncertainties nigh the oestrus capacity of water. It was later redefined equally four.1840 J exactly.^[21]

(b) The figure depends on the conversion factor betwixt "international joules" and "accented" (modern, SI) joules. Using the mean international ohm and volt ( 1.00049 Ω, 1.00034 5 ^[22]), the "international joule" is about i.00019 J, using the US international ohm and volt ( 1.000495 Ω, 1.000330 5) it is virtually 1.000165 J, giving iv.18684 and iv.18674 J, respectively.

(c) The standard atmospheric pressure tin can be taken to exist 101.325 kPa.

The two definitions most common in older literature appear to be the xv °C calorie and the thermochemical calorie. Until 1948, the latter was defined as 4.1833 international joules; the current standard of 4.184 J was chosen to accept the new thermochemical calorie correspond the same quantity of energy as before.^[19]

Usage [edit]

Diet [edit]

In a nutritional contexts, the "large" unit is used well-nigh exclusively. Information technology is mostly written "calorie" with lower instance "c" and symbol "cal", even in government publications,^{[6] [7]} although the capitalized grade "Calorie" (with symbol "Cal") or the name "kilocalorie" (with symbol "kcal") are also used, and may exist mandated by law. The SI unit of free energy kilojoule (kJ) may be used instead, in legal or scientific contexts. ^{[23] [24]}

In the United States, most nutritionists prefer the unit kilocalorie to the unit kilojoules, whereas most physiologists prefer to use kilojoules. In the majority of other countries, nutritionists prefer the kilojoule to the kilocalorie.^[25]

The unit of measurement is near usually used to express food free energy, namely the specific energy (free energy per mass) of metabolizing different types of food. For example, fat (lipids) contains 9 kilocalories per gram (kcal/g), while carbohydrates (sugar and starch) and protein contains approximately 4 kcal/k.^[26] Booze in nutrient contains vii kcal/thousand.^[27] The "large" unit is besides used to limited recommended nutritional intake or consumption, as in "calories per day".

Chemical science and physics [edit]

In other scientific contexts, the term "calorie" and the symbol "cal" almost ever refers to the pocket-sized unit; the "large" unit being generally called "kilocalorie" with symbol "kcal". It is more often than not used to express the amount of free energy released in a chemical reaction or stage modify, typically per mole of substance as in kilocalories per mole.^[28] It is also occasionally used to specify other energy quantities that relate to reaction free energy, such equally enthalpy of germination and the size of activation barriers.^[29] However, it is increasingly being superseded by the SI unit of measurement, the joule (J); and metric multiples thereof, such as the kilojoule (kJ).

The lingering utilise in chemical science is largely due to the fact that the energy released by a reaction in aqueous solution, expressed in kilocalories per mole of reagent, is numerically close to the concentration of the reagent, in moles per liter, times the alter in the temperature of the solution, in kelvin or degrees Celsius. Notwithstanding, this estimate assumes that the volumetric heat capacity of the solution is 1 kcal/L/K, which is not exact even for pure water.

See as well [edit]

• Basal metabolic rate
• Caloric theory
• Conversion of units of energy
• Empty calorie
• Nutrient energy
• Nutrition facts label
• British Thermal Unit

References [edit]

1. ^ ^{a b c} Christopher Westward. Morris (1992) Academic Press Lexicon of Scientific discipline and Applied science. 2432 pages. ISBN 9780122004001
2. ^ ^{a b c d e f} Allison Marsh (2020): "How Counting Calories Became a Science: Calorimeters defined the nutritional value of nutrient and the output of steam generators" Online commodity on the IEEE Spectrum website, dated 2020-12-29. Accessed on 2022-01-20.
3. ^ ^{a b} "Definition of Calorie". Merriam-Webster. August one, 2017. Retrieved September four, 2017.
4. ^ ^{a b} "Cambridge Dictionary: calorie". Retrieved Nov nine, 2019.
5. ^ ^{a b} "Definition of calorie noun from the Oxford Advanced American Lexicon". Retrieved November 9, 2019.
6. ^ ^{a b c} U. Due south. Food and Drug Administration (2019): "Calories on the Menu - Information for ". Online certificate at the FDA Website, dated 2019-08-05. Accessed on 2022-01-20.
7. ^ ^{a b c} U. K. National Wellness Service (2019): "What should my daily intake of calories exist?". Online document at the NHS website, dated 2019-ten-24. Accessed on 2022-01-20.
8. ^ ^{a b} Conn, Carole; Len Kravitz. "Remarkable Calorie". Academy of New Mexico. Retrieved i March 2019.
9. ^ ^{a b} Bureau International des Poids et Mesures (2019): The International System of Units (SI), 9th edition.
10. ^ ^{a b} Bureau International des Poids et Mesures (1998): The International Organisation of Units (SI), 7th edition.
11. ^ ^{a b} United nations Food and Agronomics Organization (2003): "FAO Food and Diet Paper 77: Food energy - methods of analysis and conversion factors". Accessed on 2022-01-21.
12. ^ Allain, Rhett (Feb 23, 2016). "Computing Calories by Called-for Gummy Bears to Death". Scientific American . Retrieved September 7, 2017.
13. ^ ^{a b} Hargrove, James L (2007). "Does the history of food free energy units suggest a solution to "Calorie confusion"?". Nutrition Journal. 6 (44): 44. doi:10.1186/1475-2891-6-44. PMC2238749. PMID 18086303.
14. ^ ^{a b} JL Hargrove, "history of the calorie in nutrition", J Nutr 136/12 (December 2006), pp. 2957–2961.
15. ^ Joseph Howard Raymond (1894): A Manual of Human Physiology: Prepared with Special Reference to Students of Medicine. W.B. Saunders, 376 pages.
16. ^ Marks, Percy L. (January 14, 1928). "The 2 Calories, Percy L. Marks". Nature. 121 (3037): 58. doi:10.1038/121058d0. S2CID 4068300.
17. ^ 9th CGPM, Resolution 3: Triple signal of water; thermodynamic scale with a single fixed signal; unit of measurement of quantity of oestrus (joule)., bipm.org.
18. ^ ^{a b c} International Standard ISO 31-4: Quantities and units, Part four: Oestrus. Annex B (informative): Other units given for information, especially regarding the conversion cistron. International Arrangement for Standardization, 1992.
19. ^ ^{a b} Rossini, Fredrick (1964). "Excursion in Chemical Thermodynamics, from the Past into the Future". Pure and Applied Chemical science. 8 (2): 107. doi:ten.1351/pac196408020095 . Retrieved 21 January 2013. both the It calorie and the thermochemical calorie are completely contained of the heat chapters of water.
20. ^ Lynch, Charles T. (1974). Handbook of Materials Science: Full general Properties, Book 1. CRC Press. p. 438. ISBN9780878192342 . Retrieved 8 March 2014.
21. ^ FAO (1971). "The adoption of joules as units of energy".
22. ^ International Union of Pure and Applied Chemistry (IUPAC) (1997). "ane.6 Conversion tables for units" (PDF). Compendium of Belittling Nomenclature (three ed.). ISBN0-86542-615-5 . Retrieved 31 August 2013.
23. ^ "Prospects improve for food energy labelling using SI units". Metric Views. UK Metric Association. 24 February 2012. Retrieved 17 Apr 2013.
24. ^ "SI Conventions". National Concrete Laboratory. Retrieved eight February 2016.
25. ^ Kevin T. Patton; Gary A. Thibodeau (11 Jan 2017). The Human Body in Health & Disease - E-Book. Elsevier Health Sciences. p. 537. ISBN978-0-323-40206-4.
26. ^ "How Practise Nutrient Manufacturers Calculate the Calorie Count of Packaged Foods?". Scientific American . Retrieved 2017-09-08 .
27. ^ "Calories - Fat, Protein, Carbohydrates, Alcohol. Calories per gram".
28. ^ Zvi Rappoport ed. (2007), "The Chemistry of Peroxides", Volume 2 page 12.
29. ^ Bhagavan, Northward. V. (2002). Medical Biochemistry. Academic Press. pp. 76–77. ISBN9780120954407 . Retrieved 5 September 2017.

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Source: https://en.wikipedia.org/wiki/Calorie

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