1 / 19

Concentration of solutions

This guide focuses on measuring the concentration of solutions using molarity, which represents the amount of solute in a given volume of solvent or solution. Detailed examples illustrate how to calculate molarity and perform dilution calculations using the formula MSVS = MDVD. Practical scenarios, including preparing solutions from stock concentrations, are provided for better comprehension. This resource is essential for students and professionals in chemistry who want to master the concepts of solution concentration and dilution techniques.

vernon
Download Presentation

Concentration of solutions

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 of solutions Day 4

  2. Concentration • A measurement of the amount of solute in a given amount of solvent or solution (unit of measurement = molarity) • Kind of like the “strength” of the solution

  3. Molarity Molarity (M)= mol solute L solution

  4. Molarity • Example #1: If we put 0.500 mol of sodium hydroxide into 1.00 L of solution, what is the molarity of the solution?

  5. Molarity= mol solute/L sol’n 0.500 mol NaOH M= 1.00 L = 0.500 M NaOH

  6. Example #2: What is the molarity if we have 80.0 g NaOH in 1.00 L of solution?

  7. 80.0 g NaOH 1 mol NaOH =2.00 mol Molarity= mol solute/L sol’n 40.0 g NaOH = 2.00 M NaOH 2.00 mol NaOH M= 1.00 L

  8. Molarity • Example #3: How many moles of KOH are in 0.500 L of 0.100 M KOH?

  9. Molarity= mol solute cross multiply! 1 L sol’n (0.500 L) mol KOH= (0.100 M KOH) = 0.0500 mol KOH

  10. MOLARITY • Ex 4: How many grams of KOH are in 2.75 L of 0.25 M KOH?

  11. Molarity = moles cross multiply! L Moles = Molarity * L = 0.25 mol/L * 2.75L = 0.69 moles KOH 0.69 mol KOH 56.097 g KOH = 38.7 g KOH 1 mole KOH (39)

  12. Molarity - Dilution Some chemicals are sold as pre-prepared concentrated solutions (stock solutions). To be used, stock solutions usually must be diluted.

  13. Always Add Acid

  14. 2.) Molarity - Dilution MSVS = MDVD • MS – Molarity of stock solution • VS – Volume of stock solution (L or mL) • MD – Molarity of dilute solution • VD – Volume of dilute solution (L or mL)

  15. *In dilution calculations, the units for volume must be the same.

  16. 2.) Molarity - Dilution • Example #1: How much 12.0 M HCl is required to make 2.50 L of a 0.500 M solution? • Ms * Vs = MD * VD

  17. MS VS = MD VD or M1 V1= M2 V2 MS = 12.0 M HCl MD = 0.500 M HCl VS = ?? VD = 2.50 L (0.500 M HCl) (2.50 L) VS = (12.0 M HCl) = 0.104 L HCl

  18. 2.) Molarity - Dilution • Example #2: What volume of a 1.50 M solution can be made using 0.0250 L of 18.0 M H2SO4 ? • MS VS = MD VD

  19. MS VS = MD VD MS = 18.0 M H2SO4 MD = 1.50 M H2SO4 VS = .0250 L VD = ???? (18.0 M H2SO4) (.0250 L) VD = (1.50 M H2SO4) = 0.300 L H2SO4

More Related