1 / 7

Concentration

Concentration. A primer. Definitions. Concentration is the amount of something mixed with other things in a space. The “amount” can be in grams, molecules, ions or moles The “other things” can be described as a volume, or a mass or number of moles of a material

lukas
Télécharger la présentation

Concentration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Concentration A primer

  2. Definitions • Concentration is the amount of something mixed with other things in a space. • The “amount” can be in grams, molecules, ions or moles • The “other things” can be described as a volume, or a mass or number of moles of a material • Most of the time it describes the amount of stuff dissolved in a liquid.

  3. Solutions • Solutions have two parts • A solute (often solid) • A solvent • Together they make a solution • Notice that: • The solute “disappears” • The properties of the solvent change • The volume of the solution is greater than the solvent

  4. Ways to think about concentration • “Concentrated” means there is a lot of stuff packed together tightly • In a way, it is similar to density (mass/ volume), but concentration deals with mixtures, not pure materials • Remember, in any solution there are three parts: • a solute (the thing being added), • the solvent (the mixer) • and the solution (the two combined)

  5. Formulas(Many of them!) • Molarity (M) = moles solute/ Liter solution • Molality (m) = moles solute/ kilogram solvent • Mole Fraction (c“chi”) = moles solute/ total moles solution • % concentration = grams solute/ 100 grams solvent • Parts per million (ppm) = number molecules / million molecules solution (or mole fraction x 106) • Normal (N) = moles of ions / Liter solution

  6. Ways to use formulas • In stoichiometry…one needs to convert volumes of a solution to moles • Concentration(M) x Volume (Liters) = moles • In dilutions, one adds more solvent (Liters) to get a less concentrated solution, the moles solute remain the same • Conc (M) x Volume = moles = Conc (M) x Volume (L)

  7. Molar Calculations • Volume needed to get 0.3 moles of a 6 Molar solution? • 6 M = 0.3 moles/ X liters • X= 0.05 Liters • You want 2 Liters of a 0.1 Molar solution and you have a 1 molar solution. How much is needed? • Concentration x volume = conc x volume • 0.1 Molar x 2 Liters = 1 Molar x X volume • X = 0.2 Liters (200 mL)

More Related