mole

(noun)

In the International System of Units, the base unit of amount of substance; the amount of substance of a system which contains as many elementary entities as there are atoms in 12 g of carbon-12. Symbol: mol.

Related Terms

Examples of mole in the following topics:

  • Avogador's Number

    • The number of molecules in a mole is called Avogadro's number (NA)—defined as 6.02x 1023 mol-1.
    • A mole (abbreviated mol) is a base unit in the International System of Units (SI).
    • The actual number of atoms or molecules in one mole is called Avogadro's constant (NA), in recognition of Italian scientist Amedeo Avogadro .
    • The determination of NA is crucial to the calculation of an atom's mass, since the latter is obtained by dividing the mass of a mole of the gas by Avogadro's constant.

  • Problem Solving

    • With the ideal gas law we can figure pressure, volume or temperature, and the number of moles of gases under ideal thermodynamic conditions.
    • where R is the universal gas constant, and with it we can find values of the pressure P, volume V, temperature T, or number of moles n under a certain ideal thermodynamic condition.

  • Phase Changes and Energy Conservation

    • To boil or melt one mole of a substance, a certain amount of energy is required.
    • If that amount of energy is added to a mole of that substance at boiling or freezing point, all of it will melt or boil, but the temperature won't change.

  • Isothermal Processes

    • The value of the constant is nRT, where n is the number of moles of gas present and R is the ideal gas constant.

  • Equations of State

    • where C is a constant which is directly proportional to the amount of gas, n (representing the number of moles).

  • Overview of Temperature and Kinetic Theory

    • (R: ideal gas constant, n: number of moles of gas) from a microscopic theory.

  • Calorimetry

    • To find the enthalpy change per mass (or per mole) of a substance A in a reaction between two substances A and B, the substances are added to a calorimeter and the initial and final temperatures (before the reaction started and after it has finished) are noted.
    • Dividing the energy change by how many grams (or moles) of A were present gives its enthalpy change of reaction.

  • Constant Pressure

    • Here n is the amount of particles in a gas represented in moles.

  • Adiabatic Processes

    • The value of the constant is nRT, where n is the number of moles of gas present and R is the ideal gas constant.

  • Early Models of the Atom

    • It was Avogadro who developed the idea of a fixed number of atoms and molecules in a mole.