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This is the definition declared in the modern International System of Units in 1960. [13] The definition of the joule as J = kg⋅m 2 ⋅s −2 has remained unchanged since 1946, but the joule as a derived unit has inherited changes in the definitions of the second (in 1960 and 1967), the metre (in 1983) and the kilogram . [14]
[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 ...
A unit of electrical energy, particularly for utility bills, is the kilowatt-hour (kWh); [3] one kilowatt-hour is equivalent to 3.6 megajoules.Electricity usage is often given in units of kilowatt-hours per year or other periods. [4]
This definition ultimately became the statement that 1 IT calorie is exactly 4.1868 J. [4] [8] The Btu is then calculated from the calorie as is done for the thermochemical definitions of the BTU and the calorie, as in International standard ISO 31-4 Quantities and units—Part 4: Heat and British Standard BS 350:Part 1:1974 Conversion factors ...
Pages for logged out editors learn more. Contributions; Talk; Kilojoules
Energy density is the amount of energy per mass or volume of food. The energy density of a food can be determined from the label by dividing the energy per serving (usually in kilojoules or food calories) by the serving size (usually in grams, milliliters or fluid ounces).
Bond dissociation energy for the carbon monoxide (CO) triple bond, alternatively stated: 1072 kJ/mol; 11.11eV per molecule. [21] This is the strongest chemical bond known. 2.18×10 −18 J: Ground state ionization energy of hydrogen (13.6 eV) 10 −17 2–2000×10 −17 J Energy range of X-ray photons [8] 10 −16 10 −15: femto-(fJ) 3 × 10 ...
For a fuel of composition C c H h O o N n, the (higher) heat of combustion is 419 kJ/mol × (c + 0.3 h − 0.5 o) usually to a good approximation (±3%), [2] [3] though it gives poor results for some compounds such as (gaseous) formaldehyde and carbon monoxide, and can be significantly off if o + n > c, such as for glycerine dinitrate, C 3 H 6 ...