Heterogeneous Mixtures

Heterogeneous Mixtures
Ck12 Science
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Printed: July 15, 2014
AUTHOR
Ck12 Science
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C HAPTER
Chapter 1. Heterogeneous Mixtures
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Heterogeneous Mixtures
• Define heterogeneous mixture.
• Define phase.
• Give examples of heterogeneous mixtures.
What’s the best way to eat a bag of jelly beans?
Many people open the bag and eat all the candy, no matter what flavor each piece is. Others pick through the
collection. They might say “I don’t like the orange ones.” Or maybe they just care for the lemon ones. There are
different kinds of jelly beans in the mixture and people will eat what they want and get rid of the rest.
Heterogeneous Mixtures
A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. Vegetable
soup is a heterogeneous mixture. Any given spoonful of soup will contain varying amounts of the different vegetables
and other components of the soup.
A phase is any part of a sample that has a uniform composition and properties. By definition, a pure substance or a
homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When
oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called
a phase.
In the vegetable soup example, one phase would be the liquid soup itself. This phase has vitamins, minerals, and
other components dissolved in the water. This phase would be homogeneous. The carrots, peas, corn, or other
vegetables represent other phases of the soup. The various vegetables are not mixed evenly mixed in the soup, but
are spread around at random.
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FIGURE 1.1
Oil and water do not mix, instead forming two distinct layers called phases.
The oil phase is less dense than the water phase and so the oil floats on
top of the water.
There are a large number of heterogeneous mixtures around us. Soil is composed of a variety of substances and is
often of different composition depending on the sample taken. One shovel may come up with dirt and grass while
the next shovel could contain an earthworm.
Smog is another example of a heterogeneous mixture. This murky collection of pollutants can be a mixture of water
and contaminants from burning gasoline or plastics mixed with nitric oxide derivatives and ozone. You can see that
the smog distribution in the air illustrate below is not evenly spread out, but varies from one part of the atmosphere
to another.
FIGURE 1.2
Smog in New York City.
Summary
• A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture.
• A phase is a separate layer in a heterogeneous mixture.
Practice
Questions
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Chapter 1. Heterogeneous Mixtures
Use the link below to answer the following questions:
http://antoine.frostburg.edu/chem/senese/101/matter/faq/what-is-heterogeneous.shtml
1. Why is a mixture of sand and sugar a heterogeneous mixture?
2. What are the phases in a glass of iced tea?
3. How is blood a heterogeneous mixture?
Review
Questions
1. Define a heterogeneous mixture.
2. Why is vegetable soup a heterogeneous mixture?
3. How many phases are in a heterogeneous mixture?
• heterogeneous mixture: A mixture in which the composition is not uniform throughout the mixture.
• phase: A separate layer in a heterogeneous mixture.
References
1. User:Coolgirly88/Wikipedia. http://commons.wikimedia.org/wiki/File:100_1373.JPG .
2. Flickr: Yortw. http://www.flickr.com/photos/yortw/5470226807/ .
3. Courtesy of Dr. Edwin P. Ewing, Jr./CDC. http://commons.wikimedia.org/wiki/File:SmogNY.jpg .
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