fraction

Examples of fraction in the following topics:

• Mole Fraction and Mole Percent

  • Mole fractions are dimensionless, and the sum of all mole fractions in a given mixture is always equal to 1.
  • What is the mole fraction of nitrogen in the mixture?
  • What is the mole fraction of NaCl?
  • We can now find the mole fraction of the sugar:
  • Mole fraction increases proportionally to mass fraction in a solution of sodium chloride.

• Diprotic and Polyprotic Acids

  • Given the pH and the values of Ka for each dissociation step, we can calculate each species' fractional concentration, α (alpha).
  • The fractional concentration is defined as the concentration of a particular conjugate base of interest, divided by the sum of all species' concentrations.
  • For example, a generic diprotic acid will generate three species in solution: H2A, HA-, and A2-, and the fractional concentration of HA-, which is given by:
  • The following formula shows how to find this fractional concentration of HA-, in which pH and the acid dissociation constants for each dissociation step are known:
  • The above complex equations can determine the fractional concentration of various ions from polyprotic acids.

• SI Unit Prefixes

  • The basic SI units can be expressed as fractions and multiples of basic units by using a set of simple prefixes.
  • A prefix may be used to identify multiples of the original unit or fractions of the original unit.
  • The prefixes redefine the measurement as either a multiple or a fraction of the basic unit.

• Ion Separation by Fractional Precipitation

  • Fractional precipitation can be used to determine which ions are present in a solution by taking advantage of their different solubilities.
  • One of the methods that can be applied to the solution is fractional precipitation.
  • Fractional precipitation takes advantage of the different solubilities of ions to determine which ions are present in a solution.

• Dalton's Law of Partial Pressure

  • The mole fraction is a way of expressing the relative proportion of one particular gas within a mixture of gases.
  • What is the mole fraction of neon gas?

• Vapor Pressure of Nonelectrolyte Solutions

  • Raoult's law states that the vapor pressure of an ideal solution is dependent on the vapor pressure of the pure solvent and the mole fraction of the component present in the solution.
  • In this equation, $p^{\star}_{\rm A}$ is the vapor pressure of the pure solvent and $x_{\rm A}$ is the mole fraction of the solvent.

• Average Atomic Mass

  • . + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope.
  • To calculate the average mass, first convert the percentages into fractions (divide them by 100).
  • To calculate the average atomic mass, multiply the fraction by the mass number for each isotope, then add them together.

• Writing Formulas for Polymeric Macromolecules

  • Two experimentally determined values are common: Mn , the number average molecular weight, is calculated from the mole fraction distribution of different sized molecules in a sample, and Mw , the weight average molecular weight, is calculated from the weight fraction distribution of different sized molecules.

• The Arrhenius Equation

  • Recall that the exponential part of the Arrhenius equation ($e^{\frac{-E_a}{RT}}$) expresses the fraction of reactant molecules that possess enough kinetic energy to react, as governed by the Maxwell-Boltzmann distribution.
  • Depending on the magnitudes of Ea and the temperature, this fraction can range from zero, where no molecules have enough energy to react, to unity, where all molecules have enough energy to react.
  • If the fraction were unity, the Arrhenius law would reduce to k = A.

• Reactions of Alkanes

  • A mixture of products results, and these alkanes and alkenes can be separated by fractional distillation.