1 / 33

AS Chemistry

AS Chemistry. Chapter 15 Mixtures and Solutions. Soluble song. Is it uniform throughout?. If the answer is no, the matter is a heterogeneous mixture. Considered the “least mixed.” Does not appear to be the same throughout.

erelah
Download Presentation

AS Chemistry

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. AS Chemistry Chapter 15 Mixtures and Solutions

  2. Soluble song

  3. Is it uniform throughout? • If the answer is no, the matter is a heterogeneous mixture. • Considered the “least mixed.” • Does not appear to be the same throughout. • Particles are large enough to be seen and to be separated from the mixture.

  4. Examples of heterogeneous mixtures • Sand and pebbles • Oil and water • Powdered iron and powdered sulfur

  5. Granite is a heterogeneous mixture.

  6. Sec. 1 + 4 Types of mixtures • Heterogeneous • You can tell there are 2 or more substances • Suspensions s-l a) will settle out b) can be filtered c) will scatter light (tyndall effect) d) larger than 1000 nanometers (nm) • Dirty water • Tyndall effect

  7. Colloids • Between 1 and 1000 nm dispersed particles (hard to see them) • Examples jello, milk, egg white, smoke, clouds • Tyndall effect, don’t tend to settle out, hard to filter

  8. Is it uniform throughout? • If the answer is yes, the matter is homogeneous (looks the same throughout).

  9. Solutions • A solution is a type of homogeneous mixture formed when one substance dissolves in another. • It is the best mixed of all mixtures. • A solution always has a substance that is dissolved and a substance that does the dissolving. • The substance that is dissolved is the solute and the substance that does the dissolving is the solvent. • If there is more it’s the solvent if the substances are in the same phase

  10. The universal solvent: Water

  11. Water as a solvent • Many liquid solutions contain water as the solvent. • Ocean water is basically a water solution that contains many salts. • Body fluids are also water solutions.

  12. Types of solutions Solute Solvent Example Metals dissolved in metals are called alloys.

  13. Solution animation

  14. Types of solutions

  15. d • This type of mixture is characterized by a settling of particles: • a)hydrate b) solution c) colloid d) suspension

  16. The following mixture(s) can be filtered to remove solid material. • a) colloids only c) colloids and solutions • b) suspensions only d) suspensions and colloids • Answer is b

  17. Which of the following type(s) of mixtures exhibit(s) the Tyndall effect? • a) suspensions only c) colloids and suspensions • b) colloids only d) colloids, suspensions and solutions • Answer is c

  18. Section 2 concentration • Many ways to express this • % by mass or volume • like D5W which is a .5% sugar solution or normal saline which is 0.9% sodium chloride (table salt) in IV solutions • A volume example is 70% isopropyl (rubbing) alcohol

  19. The equation is • Mass (or volume) of solute ÷ mass (or volume) of solution x 100 • How would you make up a normal saline solution? • Do problems 8-10 page 463 • Do problems 11-12 page 464 • Check your answers on page 942

  20. Molarity (M)is a more precise way to do concentration as it goes by particles not mass • Moles of solute ÷ liters (dm3) of solution • IB is mol . dm-3

  21. What is the molarity of a normal saline solution 0.9 g in 100 mL of water solution? • 0.9 / 58.5 g/mol = 0.0154 100ml /1000= .1 • 0.154 M • What is the molarity of a D5W solution 5 g of dextrose (mm 180) in 100 mL of water ? • 0.278 M

  22. Do 14-16 page 465 • Answers on page 942

  23. Preparing Molar solutions • How do you make up 500 mL of a 0.25 molar NaCl solution? • 0.25 mol/L x 0.5 L = 0.125 mol • 0.125 mol x mm(58.5 g/mol) = 7.31 g of NaCl • Put 7.31 g in a volumetric flask and dilute to 500 mL

  24. Do problems 17-19 page 467 • Check you answers on 942

  25. How many grams of NaCl are dissolved in 500.0 mL of a 0.05M solution of NaCl?A)0.05 g B)0.29 g C)1.46 g D)2.92 g • c

  26. Diluting stock solutions • Prepare 500 mL of a 0.1 M HCl solution using a 12 M stock solution • M1V1 = M2V2 • 12 M x V1 = 0.1 M x 0.500 L • V1 = (0.1 x 0.500 L) ÷ 12 • Use 0.00417 L or 4.17 mL and dilute to 500 mL

  27. Do 21 and 22 page 468 • Answers on page 942

  28. Molality (m) • To avoid the change in volume due to temperature a unit using mass is used • m = mol of solute / kg of solvent • Water 1 kg = 1L or 1g = 1mL • 4.50 grams of NaCl is added to (not diluted to)495.5 g of water. What is its molality (this is a normal saline solution) • 4.5/58.5 mol ÷.4955 kg = m

  29. Do 24 and 25 page 469 • Answers on page 942

  30. Mole fraction • One more way to express concentration • X mol of solute/ mol of solution • Change g to moles and divide by the total • What is the mole fraction of a 5% NaCl solution?

  31. Do questions 26 and 27 page 470 • Answers on page 942,3

More Related