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In chemistry, a mole map is a graphical representation of an algorithm that compares molar mass, number of particles per mole, and factors from balanced equations or other formulae. [1] They are often used in undergraduate -level chemistry courses as a tool to teach the basics of stoichiometry and unit conversion .
Since 2019, a mole of any substance has been redefined in the SI as the amount of that substance containing an exactly defined number of particles, 6.022 140 76 × 10 23. The molar mass of a compound in g/mol thus is equal to the mass of this number of molecules of the compound in grams.
Stoichiometry is not only used to balance chemical equations but also used in conversions, i.e., converting from grams to moles using molar mass as the conversion factor, or from grams to milliliters using density. For example, to find the amount of NaCl (sodium chloride) in 2.00 g, one would do the following:
The number of particles in a mole is the Avogadro number (symbol N 0) and the numerical value of the Avogadro constant (symbol N A) expressed in mol −1. [1] The SI value of the mole was chosen on the basis of the historical definition of the mole as the amount of substance that corresponds to the number of atoms in 12 grams of 12 C, [1] which ...
The molar mass is defined as the mass of a given substance divided by the amount of the substance, and is expressed in grams per mol (g/mol). That makes the molar mass an average of many particles or molecules (potentially containing different isotopes ), and the molecular mass the mass of one specific particle or molecule.
The term molality is formed in analogy to molarity which is the molar concentration of a solution. The earliest known use of the intensive property molality and of its adjectival unit, the now-deprecated molal, appears to have been published by G. N. Lewis and M. Randall in the 1923 publication of Thermodynamics and the Free Energies of Chemical Substances. [3]
normal range of hydronium ions in stomach acid (pH 1.5–3.5) [16] 5.5 mM: upper bound for healthy blood glucose when fasting [17] 7.8 mM: upper bound for healthy blood glucose 2 hours after eating [17] 10 −2: cM 20 mM: neutrinos during a supernova, 1 AU from the core (10 58 over 10 s) [18] 44.6 mM: pure ideal gas at 0 °C and 101.325 kPa [19 ...
Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. [1] For use in broader applications, it is defined as amount of substance of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase c {\displaystyle c} : [ 2 ]