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Heterogeneous and Homogenous Mixtures. Outcomes  This slide show covers the following course outcomes (refer to your “Outcomes” handout for Unit 3):

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Presentation on theme: "Heterogeneous and Homogenous Mixtures. Outcomes  This slide show covers the following course outcomes (refer to your “Outcomes” handout for Unit 3):"— Presentation transcript:

1 Heterogeneous and Homogenous Mixtures

2 Outcomes  This slide show covers the following course outcomes (refer to your “Outcomes” handout for Unit 3):  3.6  3.7  3.8  3.9  3.10

3 Homogeneous Mixtures  As we already learned, homogeneous mixtures contain two or more substances that combine to look like one substance.  Homogeneous mixtures are also called solutions.  Examples:

4 Homogeneous Mixtures  Q: Why do some substances combine to form solutions?  A: To answer this question, consider a salt water solution.  Salt is added to water.  The salt particles are attracted to the water particles and completely intermingle (mix) with the water particles.  To an observer, the particles are so intermingled that is appears as one substance.

5 Terminology  In salt water, the salt particles were attracted to the water particles causing them to completely mix.  This process is called dissolving.  The salt is known as the solute (the substance that dissolves).  The water is known as the solvent (the substance in which the solute dissolves).  Since the salt dissolves in the water, we say that the salt is soluble in water.  Using these terms, write a description for a solution of your choice.

6 Heterogeneous Mixtures  A heterogeneous mixture is a combination of two or more different types of matter that retain their own properties and that can be detected quite easily.  These mixtures may also be known as mechanical mixtures.  Examples:

7 Heterogeneous Mixtures  Q: Why do some substances combine to form mechanical mixtures?  A: Consider the mixture of pepper and water.  Pepper is added to the water  The pepper particles are more attracted to themselves than they are to the water particles.  The pepper particles “clump” together forming parts for the observer to see.

8 Terminology  Pepper does NOT dissolve in water.  Here, we say that the pepper is insoluble in water.  Example: Oil is soluble in gasoline but insoluble in water.  What does this mean?  Oil dissolves in gasoline because the oil particles are attracted to the gasoline particles. Oil is the solute while gasoline is the solvent.  Oil does not dissolve in water (oil particles are not attracted to the water particles). The oil and water do not mix.

9 Solution or Mechanical Mixture?  Q: How can you distinguish between a solution and a mechanical mixture?  A: The textbook discusses four methods: 1. Look at the mixture:  If you can see the different parts of the mixture, it is a mechanical mixture. 2. Use a microscope:  If you see only one type of mixture, it is a solution.

10 Solution or Mechanical Mixture? 3. Filtration:  If the mixture is a liquid, pour it through a filter. If there is a residue, it is a mechanical mixture (see page 247, Activity 7-2B).  Residue is the substance that is left behind in the filter.  The filtrate is the substance that passes through the filter. 4. Shine a light through the mixture:  Solutions do NOT scatter light, so you should not see a beam of light as it passes through (see page 246, Activity 7-2A).

11 Mixtures that are Mixtures  Q: Is orange juice a solution or a mechanical mixture?  A: This answer depends on whether the orange juice has pulp.  Without pulp, orange juice is a solution.  Q: Does this mean that with pulp the orange juice is considered a mechanical mixture?  NO! Scientists consider orange juice with pulp to be a mixture of mixtures. The juice is considered a solution while the juice and pulp is a mechanical mixture. It’s both!  Q: What are some more examples of mixtures that are mixtures? (See page 245 and 248)

12 Review  Read pages  Check Concepts  P. 249: #1, 2, 3, 4, and 5

13 Assignment  Read chapter 7, p  Review slide shows 3 & 4.  Complete #1-10, p and #1 on p.274.  The due date will be assigned by your teacher!


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