3/27 Notes on Mixtures

1. 3/27 Notes on Mixtures Which of the following equations shows conservation of mass in the reaction between sodium and water? • Na + H2O H2 + NaOH • Na + 4H2O 2H2+ 4NaOH • 4Na + 4H2O 2H2+ 4NaOH Draw diagram:

2. When a compound is formed, its properties are a. the same as those of its original elements. b. similar to those of its original elements. c. Completely different from its original elements.

3. What is a mixture? • A combination of 2 or more substances where there is no chemical combination or reaction • Combine physically in no specific proportions. They just blend. • Solids, liquids, and gases can be mixed to create a mixture. • You make a mixture by adding at least ONE material to another.

4. When you add a material to a gas or liquid, the material you add is called the solute , and the material you are adding to is called the solvent. • When you create a mixture, there are nonew substances formed. • Each part of a mixture keeps its original properties.

5. Mixtures vs. Compounds

6. Homogeneous vsHeterogenous • Mixtures can be heterogeneous or homogeneous. • Heterogeneous mixtures are those where the substances are not distributed evenly. They usually involve a mixture of a solid in a solid. • A mixture of stones in soil is an example of a heterogeneous mixture. Trail mix, most foods, city air.

7. Homogeneous mixtures are those where the materials are evenly distributed throughout. • Homogenized milk is an example. Lemonade, air in a vacant room, metal alloys like steel.

8. Which is a homogeneous mixture? If (a), high five the person sitting next to you If (b), low five the person sitting next to you If (d), double low five the person sitting next to you If (c),double high five the person sitting next to you

9. What type of mixture is this? Turn to a partner & discuss. Come up with some example of a common material that matches this type of mixture.

10. Types of Mixtures • Mixtures can be classified into 3 types: suspension, colloidal and solution.

11. Suspension mixtures have larger particles and are heterogeneous • They are combined with at least ONE substance visible – 1 that settles out. • Heterogeneous mixtures are suspension mixtures. Ex) Italian salad dressing, muddy water, snow globe, chicken noodle soup.

12. Colloidal mixtures fall between suspension and solution mixtures. The ingredients in colloidal mixtures are microscopic and usually homogeneous. Ex) Jell-o and Fog, milk, shampoo, mayonnaise • They are cloudy, uniform, and light is scattered.

14. Solutions are homogeneous mixtures that consist of microscopic particles and uniformly spread out molecules. Ex) Sugar or Salt in water, clear glass, jolly ranchers

16. H2O called ‘universal solvent’ because it can break down almost anything

17. Concentration = how much solute is dissolved in a solvent

18. Saturation = when solute can’t dissolve any more

19. They are clear, transparent, and light passes through them.

20. Examples of Different States in Solutions

21. Alloys • Solid solutions of metals or nonmetals dissolved in metal -usually created to strength of metals

22. OQ: Use the drawing below to answer the next question. Which statement is true about the chemical sample shown in the drawing above? a. It is a pure substance b. There are individual atoms present. c. It is a mixture of elements. d. It is a mixture of 2 compounds.

23. 3/31Separation of MixturesIQ What type of mixture is in the image below? How can you determine it?

24. Identify the following as colloid, suspension or solution: • Air • Raisins in milk • Tea • Whipped cream

25. I. Can mixtures be separated? • Can be done by physical means/processes • Separated by physical properties • density or particle size • Law of Conservation of Mass • Whatever you start with should equal what you end with • 50 g salt+ 500 g water = 550 g salt water

26. II. Types of Separation Processes • Distillation: • separates based on boiling points of substances • uses a distillation apparatus • used for H2O purification • Distilled Water @grocery store

27. Magnetism: • separates mixtures based on magnetic property in some elements • Uses a magnet, ex. Iron filings and aluminum • Substances must contain Fe, Co, or Ni • known as the iron triad

28. Centrifugation: • Separates mixtures according to densities of substances in mixture • Uses a centrifuge • Spins in circle & pulls out heavier stuff • Blood separation (CSI)

29. Sifting: • Separates mixtures based on size • uses a grate/screen • Larger particles from smaller particles • separating rocks from soil for planting • ‘panning’ for gold, • sifting for baking

30. Filtration: • Separates based on size • Uses a filter • Only miniscule particles can travel through • making coffee

31. Dissolving/Solubility: • Separates based on solubility • No special equipment • Soluble materials vs insoluble materials • NaCl will dissolve; Sulfurwill not • both elements are same color • both elements are crystals

32. Vaporization: • Separates based on boilingpoint • Uses heat • get NaCl back from seawater • why coffee cup is stained after being left out

33. Chromatography (chroma= color) • Separates mixtures based on density • Uses filter paper • Separates dyesor pigments

34. OUT ?: How would you separate a mixture of iron filings, sand and salt?