Carbon Amu

Molecular Weight Calculator

This online calculator you can use for computing the average molecular weight (MW) of molecules by entering the chemical formulas (for example C3H4OH(COOH)3 ). Or you can choose by one of the next two option-lists, which contains a series of common organic compounds (including their chemical formula) and all the elements. The molecular mass calculator will recognize the entered formula's, which are included in the list of organic compounds.
The calculator handles at most two different bracket levels. Make sure you enter the molecule of crystallization at last (e.g. C2HCl3O.H2O ).

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Molecular mass or molar mass are used in stoichiometry calculations in chemistry.
In related terms, another unit of mass often used is Dalton (Da) or unified atomic mass unit (u) when describing atomic masses and molecular masses. It is defined to be 1/12 of the mass of one atom of carbon-12 and in older works is also abbreviated as 'amu'.

Also, important in this field is Avogadro's number (N_A) or Avogadro's constant (6.0221 x 10²³).
The term 'mole' is defined in that one mole of a substance with a molecular (or atomic) mass of one (1), will have a mass of 1 gram. Or 1 mole of a substance will contain Avogadro's number of that substance. Using the above calculator you could find that e.g. a pollution of 1 gram of benzene in a certain amount of water converts to N_A/78.11≈ 7.7098 × 10²¹ molecules polluting that water!

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Carbon-12 is what was used to define the amu/Dalton. It is defined as 1/12 the mass of an atom of carbon 12. So an unbound ground state carbon-12 atom weighs 12 amu.

Carbon 12 Amu

The nucleus of carbon-12 contains six protons and six neutrons, resulting in an atomic mass of 12 amu. The nucleus of carbon-13 contains six protons and seven neutrons, resulting in an atomic mass of 13 amu. The nucleus of carbon-14 contains six protons and eight neutrons, resulting in an atomic mass of 14 amu.
One carbon-12 is assigned as exactly 12 amu. Mass of one carbon-12 atom = 12 amu. Once the mass of a standard atom is decided, mass of other atoms are determined based on their relative weight. For example, the hydrogen atom weighs only 8.40 percent of carbon-12 atom. Then the mass of hydrogen atom is calculated as follows.
To find the average atomic mass for Carbon: Average Atomic Mass = (12.0000)(.9890) + (13.0033)(0.0110) = 12.011 amu. The answer, 12.011 amu, is the same value found for Carbon on the periodic table. Exercise: Calculate the average atomic mass of Nitrogen (N) based on the information given.

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$\\pu{1amu}$ Is Defined As One Twelfth Of The Mass Of One Carbon-12 Atom. Avogadro's Number Is Defined As The Total Number Of Entities In $\\pu{12g}$...

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There Is A Lengthy Discussion Of What An Amu Is, As Well As On Avogadro's Constant In Wikipedia. See Https://en.wikipedia.org/wiki/Unified_atomic_...

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