1 / 15

Daily Inquiry :

Daily Inquiry :. Many solutions are described as concentrated or dilute. Distinguish between these two terms. A solution is made by dissolving 4.75 g of NaOH in enough water to form 250 mL of solution. (a) Express the amount of solute in moles.

yael-emerson
Télécharger la présentation

Daily Inquiry :

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. Daily Inquiry: • Many solutions are described as concentrated or dilute. Distinguish between these two terms. • A solution is made by dissolving 4.75 g of NaOH in enough water to form 250 mL of solution. (a) Express the amount of solute in moles. (b) Describe the amount of solution in liters.

  2. Today’s Objectives: • Express the concentration of a solution in units of molarity and molality. (SPI 3221.2.3) • Describe how to prepare solutions of given concentration. (SPI 3221.2.4)

  3. Concentration of a Solution • Theconcentrationof a solution is a measure of the amount of solute in a given amount of solvent or solution. • Many times solutions are referred to as “dilute” or “concentrated”. • Chemists commonly use two different ways to quantitatively express the concentration of a solution. • Molarity (M) • Molality (m)

  4. Molarity (M) • Molarity (M)is the number of moles of solute per liter of solution. moles of solute (mol) • Molarity (M) = -------------------------------- liters of solution (L)

  5. Molarity Sample Problems • A solution is made by dissolving 4.75 g of NaOH in enough water to form 250 mL of solution. What is the molarity of the solution? • How many moles of KNO3 are required to form 250 mL of a 0.50 M KNO3 solution?

  6. ITS YOUR TURN! • What is the molarity of a solution that contains 28.9 g CaCl2 dissolved in enough water to make 0.78 L of solution? A. 0.33 M B. 0.69 M C. 1.5 M D. 3.0 M

  7. Molality (m) • Molality is the concentration of a solution expressed in moles of solute per kilogram of solvent. moles of solute (mol) • Molality (m) = ----------------------------------- kilogram of solvent (kg)

  8. Molality Sample Problem • A solution was prepared by dissolving 17.1 g of glucose, C6H12O6, in 275 g of water. What is the molality (m) of this solution?

  9. Preparing Solutions • Solutions are commonly prepared by • Using solid solute • Diluting a concentrated solution • When preparing a solution from solid solute, first use the molarity equation determine the mass of the solute required.

  10. Preparing a Solution from Solid Solute • An experiment calls for 250 mL of a 0.10 M KMnO4 solution. How many grams of solid KMnO4 are required to make the solution? Explain how you would create this solution.

  11. What Do You Think? • How many grams of sodium chloride (NaCl) are required to prepare 500.0 mL of a 0.100 M solution? A. 1.46 g B. 2.93 g C. 29.3 g D. 58.5 g

  12. Preparing Solutions from Other Solutions • Many times solutions are prepared by diluting concentrated solutions. These are called stock solutions. • Dilution = process of adding water to a stock solution to achieve the molarity desired for a particular solution. • Adding water increases the volume of the solution and this causes the concentration to decrease. • Dilution Equation: M1V1 = M2V2

  13. Preparing a Solution by Dilution • How many milliliters of 12 M HCl stock solution are needed to make 500 mL of a 0.20 M HCl solution? Explain how you would prepare this solution.

  14. Practice Question • If 250.0 mL of a 0.96 M solution of acetic acid are diluted to 800.0 mL, what will be the molarity of the final solution? A. 0.19 M B. 0.24 M C. 0.30 M D. 0.77 M

  15. After reflecting on today’s lesson, complete three of the sentence starters on your note card and hand it to me as you leave today. Sentence Starters I’ve learned… I was surprised… I’m beginning to wonder… I would conclude… I now realize that… Outcome Sentences

More Related