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Chapter 4

Chapter 4. Elements, Compounds & Mixtures Section III. Section 3 - Mixtures. III. MIXTURES A.  Properties of mixtures – A Mixture is a combination of chemical substances that are not chemically combined. 1. Substances in a mixture retain their

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Chapter 4

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  1. Chapter 4 Elements, Compounds & Mixtures Section III

  2. Section 3 - Mixtures • III. MIXTURES • A. Properties of mixtures – A Mixture is a combination of chemical substances that are not chemically combined. • 1. Substances in a mixture retain their identity. • a. In some mixtures you can see the individual pieces (pizza). Introductory movie www.anneyiz.biz/print/

  3. Section 3 - Mixtures • b. In other Mixtures you cannot see all of the components (Salt water). Pizza dough lemonade http://www.eriding.net/media/photos/design_tech/food/050114_rfoster_mp_dt_food_dough3.jpg http://travis.kroh.net/archives/00309004.jpg

  4. Section 3 - Mixtures • 2. Mixtures can be physically separated. • a.  Picking the pieces of the mixture apart. • Either by hand for big particles (pizza) or by a filter for medium sized particles. (Coffee grounds) or distillation (for really small particles) http://www.yourdictionary.com/images/ahd/jpg/A4distln.jpg

  5. Section 3 - Mixtures • c. Magnets- can sort out metals that can be magnetized. d. Density - can be used to separate mixtures. By adding water if one of the items has a density less than water or Centrifuge-can spin items of different in to layers. e. Some mixtures need to be separated using several steps. http://www.teach-nology.com/web_tools/science_lab/centrifuge.gif http://www.twpg.com.au/Retail/images/magnets1.gif

  6. Section 3 - Mixtures 3. The components of a mixture do not have a definite ratio. a. The amount of things in a mixture does not matter. b. The air is made of nitrogen, oxygen and other gases including water. Some days the air has more water than others. Air is a mixture.

  7. Section 3 - Mixtures • B. Solutions- • 1. A solution is a mixture that appears to be a • single substance but is composed of particles • of two or more substances distributed evenly • amongst each other. • The pieces of the mixture are VERY small. So small that they cannot be seen, filtered or even reflect light

  8. Section 3 – Mixtures • a. Because it has the same appearance and • properties through out the mixture it is • often described as a homogeneous • mixture. • b. The process in which the particles separate and • spread evenly throughout a mixture is called • dissolving. • c. The solute is the substance that is dissolved and • the solvent is the substance the solute is • dissolved in. • Solutions movie

  9. d. A solute is soluble or able to dissolve. If a substance is insoluble it will form a mixture that is not homogeneous and therefore is not a solution.

  10. Section 3 - Mixtures • e. If two liquids or two gasses combine to form a • solution the substance with the greater volume • is the solvent. f.  Alloys are solid solutions of metals or non metals dissolved in metals. For example brass is an alloy of Zinc dissolved in copper. http://www.grybmusic.com/percussion/Percussion%20Photos/P7110056%20brass%20jingle%20bells.jpg Alloy Video-Unitedstreaming Brass This is an alloy of indium Gallium and tin that is a liquid at room temperature http://sci-toys.com/scitoys/scitoys/thermo/liquid_metal/two_vials.jpg

  11. Section 3 - Mixtures • 2. Particles in solutions are extremely small. So small that • they never settle out, cannot be filtered out and they do • not even scatter light. • 3. Concentration is a measure of how much solute is • dissolved in the solvent. Deep concentration! http://shopping.animazing.com/gallery/willardson_04/art/small/images/505-1080%20The%20Picture%20Of%20Concentration%20%23%2014-2%20(S%2005-03)%2011.75x8.5.jpg

  12. Section 3 - Mixtures • b. Solutions can be described as concentrated or dilute but these are not specific descriptions. • c. A solution that contains all the solute it can hold at a given temperature is said to be saturated. An unsaturated solution contains less than it can hold.

  13. Section 3 - Mixtures • 4. 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. • a. Solubility is expressed in grams of solute per 100mL of solvent. • b. There is a solubility chart on p 95. • c. The solubility of gasses in liquids decreases • as temperature is raised • SOLUBILITY CHART FROM TEXT

  14. Section 3 - Mixtures • 5. What effects how fast a solid dissolves? • a. Mixing- stirring or shaking helps particles separate • and mix with the solvent. • b. Heating- causes particles to move more quickly • causing solvent to spread out and mix with solvent. • c. Crushing- increases the amount of contact between • the solute and the solvent. Allowing the solvent to • dissolve more quickly.

  15. Section 3 - Mixtures crushing http://altura.speedera.net/ccimg.catalogcity.com/220000/226000/226022/products/lg_9403112.jpg Mixing Heating http://www.darkdarling.com/photos/stirring.jpg http://www.american.edu/ted/images4/heating.GIF

  16. Section 3 - Mixtures • C. Suspensions- a mixture in which particles are dispersed throughout the liquid or the gas but are large enough that they settle out. • Suspension Video-Courtesy Unitedstreaming • 1. The particles are insoluble so they do not dissolve. • 2. Suspensions are usually described as heterogeneousmixtures (video). Because the different components are easily seen.

  17. Section 3 - Mixtures • 3. Characteristics of suspensions: • a. Particles are fairly large and they scatter or • block light. • b. Particles are too heavy to stay mixed without • being stirred or shaken. • c. Passing it through a filter can separate a • suspension.

  18. Section 3 - Mixtures • D. Colloids-a mixtures in which the particles are dispersed through out but are not heavy enough to settle out. Colloid Video-Unitedstreaming • 1. Colloids have properties of both solutions and • suspensions. • 2. The particles in a colloid are large enough to scatter • a beam of light. • 3. The particles in a colloid cannot be filtered out of • the mixture.

  19. Section 3 - Mixtures • Examples of colloids include- milk, gelatin, whipped cream, deodorant, and mayonnaise. Photos courtesy google.com

  20. Build comparison 5 block chart • Note to Mrs. Martin remember that they have difficulties comparing the substances re teach how this goes so the tests will be ok

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