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Mixtures

Mixtures. Homogenous or Heterogenous ?. BELLWORK. What is a mixture? How can it be separated ? Can you provide another example ?. BELLWORK. Mixtures. a physical blend of two or more substances composition varies (Air/ Salad)

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Mixtures

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  1. Mixtures HomogenousorHeterogenous?

  2. BELLWORK • Whatis a mixture? • How can itbeseparated? • Can youprovideanotherexample?

  3. BELLWORK

  4. Mixtures • a physicalblend of twoor more substances • compositionvaries (Air/ Salad) • There are twotypes of mixtures: homogenous and heterogenous

  5. Mixtures Heterogenous mixtures • type of mixture thatisnotthesameallthewaythrough (not “uniform”) Ifyouweretosampleoneportion of such a mixture, it’scompositionwouldbedifferentfromthat of anotherportion.

  6. Mixtures Homogenous mixture • type of mixture thatisthesameallthewaythrough (saidtobe “uniform”) • parts are evenlydistributed (mixed) throughoutthesample

  7. Alloys: mixture of metals Stainless steel is a mixture of iron and chromium. Brass is an alloy of copper and zinc.

  8. Remember…

  9. Air Salt water Tea Brass Vinegar Hydrogen peroxide Steel Salad dressing Apple Sand Paint Granite Laundry detergent Cereal Homogenous or Heterogenous?

  10. Homo orhetero -genous mixture?

  11. Homo orhetero -genous mixture?

  12. Solutions are VERY well mixed homogeneous mixtures.. • Dissolving – The process in which particles of substances separate and spread evenly amongst each other. • Solute – part that is soluble, gets dissolves • Soluble: is able to be dissolved • Insoluble : is unable to dissolve • Solvent– substance that does the dissolving • Water is the universal solvent

  13. Solutions

  14. Saturated and Unsaturated Solutions piers.wikispaces.com/file/view/saturated+and+unsaturated.ppt

  15. How much can be dissolved? • Do you think there is a limit to how much can be dissolved in a solvent? • Can you make it more and more concentrated?

  16. Dissolving • How does something dissolve to make a solution? • Dissolving Animation • Activity: Measure out 20mL of water and 5 g of sugar. Dissolve. Add 5 more grams and continue until saturated. Keep track of the total amount of sugar to calculate the final concentration in g/mL.

  17. Saturated and Unsaturated Solutions • unsaturated, saturated and supersaturated solutions. • Fill-in the blanks using the following terms: • concentrated solute dilute saturated solvent sugar concentration water solution • 1. In this demo the _______________ is the _________________, and the_________________ is the ________________. • 2. As we continue to add more sugar the _______________________ becomes more and more _______________________. • 4. The final solution can be described as having a _____________________________ of ________g/ mL • 5. When we can't add any more sugar, we say that the solution is __________________. • 6. From your experiences are there any other ways you could think to get more solute into the solution?

  18. Solvent particles • More solute could dissolve at the same temperature. • More solvent particles are available to dissolve solute. Solute particles Unsaturated Solution

  19. Saturated • No more solute will dissolve at a specific temperature. • All of the solvent particles are already attracted to as many solute particles as they can be. Saturated Solution

  20. Solubility • The solubility of a solute is the amount of solute needed to make a saturated solution using a given amount of solvent at a certain temperature. • Solubility is usually expressed in grams of solute per 100 ml of solvent (g/100ml) • Three (3) methods that affect solubility • Mixing, stirring, or shaking • Heating • Crushing or grinding

  21. SuperSaturated Solution • Has been heated to dissolve the maximum amount of solute and cooled without stirring. • When a single crystal is added to the solution, it grows until the whole solution becomes a solid.

  22. Colloids: homogenous mixtures that disperses light • Colloid • aka a colloidal dispersion • tiny particles are suspended in some medium • the particles are single large molecules or • the particles are groups of molecules or ions from 1 to 1000 nm.

  23. Colloids • Type of colloid depends on the medium and the dispersed phase

  24. Colloids

  25. Colloid • What stabilizes a colloid? • Electrostatic repulsion • A colloid is neutral • BUT, when a colloid is placed in an electric field, the particles all migrate to the same electrode. • The colloid attracts ions of the same charge which surround the colloid particle. • Ions of the opposite charge surround the first layer of ions. • Being surrounded by ion, the colloid particles repel other colloid particles, and so are unable to aggregate to precipitate out

  26. Separating Mixtures

  27. Separating Mixtures Supposeyouhad a mixture of ironnails, salt and water… Howwouldyouseparatethis mixture completely? Basedonwhichphysicalpropertieswouldyou base yourmethod ?

  28. Separating Mixtures How would you separate the components in tap water? Distillation A liquid is boiled to produce vapor that is then condensed again to a liquid

  29. Separating Mixtures

  30. Mixtures Sample problem How can a mixture of iron fillings and aluminum fillings be separated? 1.-Analyze: Plan a problem solving strategy List the properties of iron and aluminum and look for something that would be useful in separating the mixture

  31. Iron: Metal Grayish Not soluble in water Attracted to a magnet Aluminum: Metal Grayish Not soluble in water Not attracted to magnets Mixtures 2.- Solve: Apply the problem-solving strategy. Make use of a property that differentiates the metals; use a magnet to attract the iron fillings.

  32. Mixtures 3.-Evaluate: Does the result make sense? Because the magnet attracts iron but not aluminum filings, the iron would be removed while the aluminum would be left behind.

  33. Mixtures • Common Techniques for Separating Mixtures Distillation – separates a mixture based on boiling points of the component. Examples : saltwater crude oil into gasoline and kerosene Magnet– separates iron from other objects Centrifuge – spins and separates according to densities

  34. Practice Problems • What physical properties could be used to separate iron filings from salt? • Which of the following are homogenous? heterogenous? 1.-Spaghetti sauce 4.-Cough syrup 2.-Glass 5.-Mixture of nitrogen gas 3.-Muddy Water and helium gas

  35. Resources Edhelper: Mixtures Solutions and Compounds Reading Temperature and Solubility Mixtures and Compounds Lab Simulation Elements, compounds, mixture lab Elements, Compounds, Mixtures Oh My Solubility Activity Chromatography Lab Messing With Mixtures

  36. This powerpoint was kindly donated to www.worldofteaching.com http://www.worldofteaching.com Is home to well over a thousand powerpoints submitted by teachers. This a free site. Please visit and I hope it will help in your teaching

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