dilution

Examples of dilution in the following topics:

• Dilutions of Solutions

  • What is the final concentration of the diluted solution?
  • Serial dilutions involve diluting a stock or standard solution multiple times in a row.
  • Typically, the dilution factor remains constant for each dilution, resulting in an exponential decrease in concentration.
  • This video shows how to solve two dilution problems, using the standard dilution formula, M1V1 = M2V2.
  • Dilutions can sometimes be visually observed.

• Using Molarity in Calculations of Solutions

  • You might notice that the above formula bears some resemblance to our dilution formula:
  • Because we now know that MV = mol, we can simplify our the dilution formula to the following:
  • After all, in any dilution, what changes is the amount of solvent, while the number of moles of solute remains constant throughout.

• Molarity

  • Dilution is the process of reducing the concentration of a solute in a solution, usually by adding more solvent.
  • If 60.0 mL of 5.0 M HCl is used to make the desired solution, the amount of water needed to properly dilute the solution to the correct molarity and volume can be calculated:
  • We are asked to find c2, which is the molarity of the diluted solution.
  • We calculate that we will have a 0.05 M solution, which is consistent with our expectations considering we diluted 25 mL of a concentrated solution to 2500 mL.

• Polyprotic Acid Titrations

  • If a dilute solution of oxalic acid were titrated with a sodium hydroxide solution, the protons would react in a stepwise neutralization reaction.
  • The titration of dilute oxalic acid with sodium hydroxide (NaOH) shows two distinct neutralization points due to the two protons.

• Boiling Point and Water Solubility

  • The basicity of amines (next section) allows them to be dissolved in dilute mineral acid solutions, and this property facilitates their separation from neutral compounds such as alcohols and hydrocarbons by partitioning between the phases of non-miscible solvents.

• Oxidation

  • Other reagents, among them aqueous potassium permanganate and dilute bromine, effect the same transformation.

• The Leveling Effect

  • As an interesting aside, the presence of hydronium ion itself often comes under question, particularly in dilute solution.
  • The presence of hydronium ion in dilute aqueous solution is unlikely.

• Reactions of Substituent Groups

  • These include zinc or tin in dilute mineral acid, and sodium sulfide in ammonium hydroxide solution.
  • Direct nitration of phenol (hydroxybenzene) by dilute nitric acid gives modest yields of nitrated phenols and considerable oxidative decomposition to tarry materials; aniline (aminobenzene) is largely destroyed.

• pOH and Other p Scales

  • Investigate whether changing the volume or diluting with water affects the pH.

• Heat of Solution

  • The heat of solution, also referred to the enthalpy of solution or enthalpy of dissolution, is the enthalpy change associated with the dissolution of a solute in a solvent at constant pressure, resulting in infinite dilution.