Calorie

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This COMMODITY is about the units of energy. For added uses, see Calorie (disambiguation).
The name calorie is acclimated for two units of energy.
The baby calorie or gram calorie (symbol: cal) is the almost bulk of activity bare to accession the temperature of one gram of baptize by one bulk Celsius.[1]
The ample calorie, kilogram calorie, comestible calorie, nutritionist's calorie, comestible calorie, Calorie (capital C)[2] or aliment calorie (symbol: Cal) is about the bulk of activity bare to accession the temperature of one kilogram of baptize by one bulk Celsius. The ample calorie is appropriately according to 1000 baby calories or one kilocalorie (symbol: kcal).[1]
Although these units are allotment of the metric system, they accept been abolished in the International Arrangement of Units by the joule. One baby calorie is about 4.2 joules (so one ample calorie is about 4.2 kilojoules). The agency acclimated to catechumen calories to joules at a accustomed temperature is numerically agnate to the specific calefaction accommodation of baptize bidding in joules per kelvin per gram or per kilogram. The absolute about-face agency depends on the analogue adopted.
In animosity of its non-official status, the ample calorie is still broadly acclimated as a assemblage of aliment activity in the US, UK and some added Western countries. The baby calorie is aswell generally acclimated for abstracts in chemistry, although the amounts complex are about recorded in kilocalories.
The calorie was aboriginal authentic by Nicolas ClГ©ment in 1824 as a assemblage of heat,[3] and entered French and English dictionaries amid 1841 and 1867. The chat comes from Latin calor acceptation "heat".
Contents [hide]
1 Definitions
2 Usage
2.1 Nutrition
2.2 Chemistry
3 See also
4 References

Definitions

The activity bare to access the temperature of a accustomed accumulation of baptize by 1 В°C depends on the atmospheric burden and the starting temperature. Accordingly, several altered complete definitions of the calorie accept been used.
The burden is usually taken to be the accepted atmospheric burden (101.325 kPa). The temperature access can be bidding as one kelvin, which agency the aforementioned as an accession of one bulk Celsius.
Name Symbol Conversions Notes
Thermochemical calorie calth в‰Ў 4.184 J
≈ 0.003964 BTU ≈ 1.163×10−6 kWh ≈ 2.611×1019 eV
the bulk of activity according to absolutely 4.184 joules [4][5][6][7]
4 °C calorie cal4 ≈ 4.204 J
≈ 0.003985 BTU ≈ 1.168×10−6 kWh ≈ 2.624×1019 eV
the bulk of activity appropriate to balmy one gram of air-free baptize from 3.5 to 4.5 В°C at accepted atmospheric pressure.
15 °C calorie cal15 ≈ 4.1855 J
≈ 0.0039671 BTU ≈ 1.1626×10−6 kWh ≈ 2.6124×1019 eV
the bulk of activity appropriate to balmy one gram of air-free baptize from 14.5 to 15.5 В°C at accepted atmospheric pressure. Beginning ethics of this calorie ranged from 4.1852 J to 4.1858 J. The CIPM in 1950 arise a beggarly beginning bulk of 4.1855 J, acquainted an ambiguity of 0.0005 J.[4]
20 °C calorie cal20 ≈ 4.182 J
≈ 0.003964 BTU ≈ 1.162×10−6 kWh ≈ 2.610×1019 eV
the bulk of activity appropriate to balmy one gram of air-free baptize from 19.5 to 20.5 В°C at accepted atmospheric pressure.
Mean calorie calmean ≈ 4.190 J
≈ 0.003971 BTU ≈ 1.164×10−6 kWh ≈ 2.615×1019 eV
1вЃ„100 of the bulk of activity appropriate to balmy one gram of air-free baptize from 0 to 100 В°C at accepted atmospheric pressure.
International Steam table calorie (1929) ≈ 4.1868 J
≈ 0.0039683 BTU ≈ 1.1630×10−6 kWh ≈ 2.6132×1019 eV
1вЃ„860 all-embracing watt hours = 180вЃ„43 all-embracing joules exactly.[note 1]
International Steam Table calorie (1956) calIT в‰Ў 4.1868 J
≈ 0.0039683 BTU ≈ 1.1630×10−6 kWh ≈ 2.6132×1019 eV
1.163 mWВ·h = 4.1868 J exactly. This analogue was adopted by the Fifth All-embracing Conference on Properties of Steam (London, July 1956).[4]
Jump up ^ The amount depends on the about-face agency amid all-embracing joules and complete (modern) joules. Application the beggarly all-embracing ohm and volt (1.00049 О©, 1.00034 V[8]), the all-embracing joule is about 1.00019 J, application the US all-embracing ohm and volt (1.000495 О©, 1.000330 V) it is about 1.000165 J, giving 4.18684 J and 4.18674 J, respectively.
2. The two definitions a lot of accepted in earlier abstract arise to be the 15 В°C calorie and the thermochemical calorie.

Usage

The calorie was aboriginal authentic accurately to admeasurement activity in the anatomy of heat, abnormally in beginning calorimetry.
Nutrition[edit]
In comestible contexts, the kilojoule (kJ) is the SI assemblage of aliment energy. However, the calorie and kilocalorie are still in accepted use.[9]
In these contexts, confusingly, the chat "calorie" and "kilocalorie" accredit to agnate units (the above to the ample calorie and the closing to 1000 baby calories). Sometimes, in an attack to abstain confusion, the ample calorie is accounting as "Calorie" (with a basic "C"). This assemblage is not consistently followed, and not explained to the boilerplate getting clearly.
These quantities are generally acclimated for the absolute bulk of aliment activity (e.g., in a meal) and for the specific energy, namely bulk of activity per assemblage of accumulation (e.g. "calories per gram", "calories per serving"). Comestible requirements or intakes are generally bidding in calories per day.
Chemistry[edit]
In accurate contexts, the appellation calorie about consistently refers to the baby calorie. Even admitting it is not an SI unit, it is still acclimated in chemistry. For example, the activity appear in a actinic acknowledgment per birthmark of reagent is occasionally bidding in kilocalories per mole.[10][11] Traditionally, this use was abundantly due to the affluence with which it could be affected in class reactions, abnormally in aqueous solution: a aggregate of reagent attenuated in baptize basic a solution, with absorption bidding in moles per liter (1 liter belief 1 kg), will abet a temperature change in degrees Celsius in the absolute aggregate of baptize solvent, and these quantities (volume, molar absorption and temperature change) can again be acclimated to account activity per mole. It is aswell occasionally acclimated to specify activity quantities that chronicle to acknowledgment energy, such as enthalpy of accumulation and the admeasurement of activation barriers.[citation needed] However, its use is getting abolished by the SI unit, the joule, and multiples thereof such as the kilojoule.