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Heterogeneous and Homogeneous Mixtures
The Difference Between Heterogeneous and Homogeneous Mixtures
By Anne Marie Helmenstine,
Ph.D.
The terms heterogeneous and homogeneous refer to mixtures of materials
in chemistry.
The difference between heterogeneous and homogeneous
mixtures is the degree to which the materials are mixed together and the
uniformity of their composition.
A homogeneous mixture is
a mixture in which the components that make up the mixture are uniformly
distributed throughout the mixture.
The composition of the mixture is the same throughout.
There is only one phase of matter observed in a homogeneous
mixture at a time.
So, you wouldn't observe both a liquid and a gas or a
liquid and a solid in a homogeneous mixture.
Homogeneous Mixture Examples
There are several examples of homogeneous mixtures
encountered in everyday life:
· Air
· Sugar water
· Rainwater
· Vodka
· Vinegar
· Dishwashing detergent
· Steel
You can't pick out components of a homogeneous mixture or
use simple mechanical means to separate them.
You can't see individual chemicals or ingredients in this
type of mixture. Only one phase of matter is present in a homogeneous mixture.
A heterogeneous mixture is a
mixture in which the components of the mixture are not uniform or have
localized regions with different properties.
Different samples from the mixture are not identical to
each other.
There are always two or more phases in a heterogeneous
mixture, where you can identify a region with properties that are distinct from
those of another region, even if they are the same state of matter (e.g.,
liquid, solid).
Heterogeneous Mixture Examples
Heterogeneous mixtures are more common than homogeneous
mixtures. Examples include:
· Cereal in milk
· Vegetable soup
· Pizza
· Blood
· Gravel
· Ice in soda
· Salad dressing
· Mixed nuts
· Bowl of colored candies
· Soil
Usually, it's possible to physically separate components of
a heterogeneous mixture.
For example, you can centrifuge (spin out) solid blood
cells to separate them from the plasma of blood.
You can remove ice cubes from soda.
You can separate candies according to color.
Telling Homogeneous and Heterogeneous Mixtures Apart
Mostly, the difference between the two types of mixtures is a matter of scale.
If you look closely at sand from a beach, you can see the
different components, including shells, coral, sand, and organic matter. It's a
heterogeneous mixture.
If, however, you view a large volume of sand from a
distance, it's impossible to discern the different types of particles.
The mixture is homogeneous. This can seem confusing!
To identify the nature of a mixture, consider its sample
size. If you can see more than one phase of matter or different regions in the
sample, it is heterogeneous.
If the composition of the mixture appears uniform no matter
where you sample it, the mixture is homogeneous.
Anne
Marie Helmenstine, Ph.D.
Chemistry
Expert
Education
Ph.D.,
Biomedical Sciences, University of Tennessee at Knoxville
B.A.,
Physics and Mathematics, Hastings College
Introduction
Ph.D.
in biomedical sciences from the University of Tennessee at Knoxville - Oak
Ridge National Laboratory.
Science
educator with experience teaching chemistry, biology, astronomy, and
physics at the high school, college, and graduate levels.
ThoughtCo
and About Education chemistry expert since 2001.
Widely-published
graphic artist, responsible for printable periodic tables and other
illustrations used in science.
Experience
Anne
Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education
since 2001, and other sciences since 2013. She taught chemistry, biology,
astronomy, and physics at the high school, college, and graduate levels.
She has worked as a research scientist and also abstracting and indexing
diverse scientific literature for the Department of Energy.
In
addition to her work as a science writer, Dr. Helmenstine currently serves as a
scientific consultant, specializing in problems requiring an interdisciplinary
approach. Previously, she worked as a research scientist and college professor.
Education
Dr.
Helmenstine holds a Ph.D. in biomedical sciences from the University of
Tennessee at Knoxville and a B.A. in physics and mathematics with a minor
in chemistry from Hastings College. In her doctoral work, Dr. Helmenstine
developed ultra-sensitive chemical detection and medical diagnostic tests.
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