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Historically, the mole was defined as the amount of substance in 12 grams of the carbon-12 isotope.As a consequence, the mass of one mole of a chemical compound, in grams, is numerically equal (for all practical purposes) to the mass of one molecule or formula unit of the compound, in daltons, and the molar mass of an isotope in grams per mole is approximately equal to the mass number ...
The formal charge of any atom in a molecule can be calculated by the following equation: = where V is the number of valence electrons of the neutral atom in isolation (in its ground state); L is the number of non-bonding valence electrons assigned to this atom in the Lewis structure of the molecule; and B is the total number of electrons shared ...
However, one gram of hydrogen reacts with 8 grams of oxygen to give water or with 35.5 grams of chlorine to give hydrogen chloride: hence 8 grams of oxygen and 35.5 grams of chlorine can be taken to be equivalent to one gram of hydrogen for the measurement of equivalent weights. This system can be extended further through different acids and bases.
In chemistry, the electrochemical equivalent (Eq or Z) of a chemical element is the mass of that element (in grams) transported by a specific quantity of electricity, usually expressed in grams per coulomb of electric charge. [1] The electrochemical equivalent of an element is measured with a voltameter.
Because a dalton, a unit commonly used to measure atomic mass, is exactly 1/12 of the mass of a carbon-12 atom, this definition of the mole entailed that the mass of one mole of a compound or element in grams was numerically equal to the average mass of one molecule or atom of the substance in daltons, and that the number of daltons in a gram ...
Related to the Faraday constant is the "faraday", a unit of electrical charge. Its use is much less common than of the coulomb, but is sometimes used in electrochemistry. [4] One faraday of charge is the charge of one mole of elementary charges (or of negative one mole of electrons), that is, 1 faraday = F × 1 mol = 9.648 533 212 331 001 84 × ...
where M is the molar mass of the substance (usually given in SI units of grams per mole) and v is the valency of the ions. For Faraday's first law, M, F, v are constants; thus, the larger the value of Q, the larger m will be.
The electric charge of a macroscopic object is the sum of the electric charges of the particles that it is made up of. This charge is often small, because matter is made of atoms, and atoms typically have equal numbers of protons and electrons, in which case their charges cancel out, yielding a net charge of zero, thus making the atom neutral.