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  2. Thermodynamic activity - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_activity

    The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.

  3. Stoichiometry - Wikipedia

    en.wikipedia.org/wiki/Stoichiometry

    Mole ratio: Convert moles of Cu to moles of Ag produced; Mole to mass: Convert moles of Ag to grams of Ag produced; The complete balanced equation would be: Cu + 2 AgNO 3 → Cu(NO 3) 2 + 2 Ag. For the mass to mole step, the mass of copper (16.00 g) would be converted to moles of copper by dividing the mass of copper by its molar mass: 63.55 g/mol.

  4. Extent of reaction - Wikipedia

    en.wikipedia.org/wiki/Extent_of_reaction

    Consider the reaction A ⇌ 2 B + 3 C. Suppose an infinitesimal amount of the reactant A changes into B and C. This requires that all three mole numbers change according to the stoichiometry of the reaction, but they will not change by the same amounts.

  5. Avogadro constant - Wikipedia

    en.wikipedia.org/wiki/Avogadro_constant

    The Avogadro constant, commonly denoted N A [1] or L, [2] is an SI defining constant with an exact value of 6.022 140 76 × 10 23 mol −1 (reciprocal moles). [3] [4] It is this defined number of constituent particles (usually molecules, atoms, ions, or ion pairs—in general, entities) per mole and used as a normalization factor in relating the amount of substance, n(X), in a sample of a ...

  6. Time-of-flight mass spectrometry - Wikipedia

    en.wikipedia.org/wiki/Time-of-flight_mass...

    Laser ionization time-of-flight mass spectrometer where ions are accelerated and separated by mass in a field-free drift region before detection Bendix MA-2 Time-of-Flight Mass Spectrometer, 1960s. Time-of-flight mass spectrometry (TOFMS) is a method of mass spectrometry in which an ion's mass-to-charge ratio is determined by a time of flight ...

  7. Mass diffusivity - Wikipedia

    en.wikipedia.org/wiki/Mass_diffusivity

    Diffusivity, mass diffusivity or diffusion coefficient is usually written as the proportionality constant between the molar flux due to molecular diffusion and the negative value of the gradient in the concentration of the species. More accurately, the diffusion coefficient times the local concentration is the proportionality constant between ...

  8. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    In a chemical reaction, the half-life of a species is the time it takes for the concentration of that substance to fall to half of its initial value. In a first-order reaction the half-life of the reactant is ln(2)/ λ , where λ (also denoted as k ) is the reaction rate constant .

  9. Mole fraction - Wikipedia

    en.wikipedia.org/wiki/Mole_fraction

    In chemistry, the mole fraction or molar fraction, also called mole proportion or molar proportion, is a quantity defined as the ratio between the amount of a constituent substance, n i (expressed in unit of moles, symbol mol), and the total amount of all constituents in a mixture, n tot (also expressed in moles): [1]