Heterogeneous Mixture — Definition & Examples
What is a heterogeneous mixture?
A heterogeneous mixture is a non-uniform mixture with visible, individual items or particles. Heterogeneous mixtures contain two or more constituent parts that mix but remain physically separate. The components’ chemical properties do not change, and the individual components are observable with the naked eye.
Examples are a bowl of hard candies, a school assembly of students, a pizza, or a salad. Heterogeneous mixtures contrast with homogeneous mixtures, which have a uniform composition.
Recall that a mixture combines two or more substances that are not linked through chemical bonds. Mixtures are not compounds or elements; they are not pure substances but can be made with them.
Properties of heterogeneous mixtures
Heterogeneous mixtures display these properties:
Heterogeneous mixtures contain at least two components, ingredients, or different phases (any part of a sample that has uniform composition and properties).
Mixtures can usually be separated.
Phases mix together but retain their own chemical identity.
Mixtures with different states of matter (gas, liquid, solid) are always heterogeneous.
Examples of a heterogeneous mixture
Heterogeneous mixtures can appear in all common phases of matter, including solids, liquids, and gases. Any mixture combining states of matter is heterogeneous, as with solid salt in water, ice cubes in fruit juice, or carbon dioxide bubbles rising in a glass of soda.
Five kinds of heterogeneous mixtures are solids, liquids, gases, colloids, and suspensions.
Solid heterogeneous mixtures
Common household heterogeneous mixtures include mixed nuts, salad, tacos, pizza, and mixed vegetables.
Concrete is a heterogeneous mixture of crushed stone, sand, water, and cement. Beach sand and soil are other examples.
Liquid heterogeneous mixtures
Liquids that will not mix (immiscible liquids) are always heterogeneous mixtures. This is why Italian salad dressing must be shaken before being poured on: the oil and vinegar are immiscible.
Other liquid heterogeneous mixtures include:
seawater (not saltwater alone, but all the living and nonliving things mixed into the saltwater)
orange juice with pulp
silt-filled river water
Gas heterogeneous mixtures
Gases typically are not heterogeneous, but they can be. Heterogeneous gases include mist, fog, smog (a mixture of smoke and fog), and smoke.
Colloids and suspensions
Two kinds of heterogeneous mixtures are easily confused: colloids and suspensions. Their principal differences are particle sizes in the mixture and how those particles settle out.
A colloid is a heterogeneous mixture with particles in between the size of particles found in suspensions (big particles) and solutions (very small particles).
Colloids are heterogeneous mixtures in which small particles of one substance are evenly distributed throughout a different substance and do not settle. Gels and emulsions are colloids.
Colloids disperse light. A common example of this is observing rays of light in forests because the fog or mist is a colloid. This phenomenon is known as the Tyndall Effect.
Whole milk is a colloid, as is canned shaving cream and toothpaste.
Suspensions are heterogeneous mixtures that have the largest particles, and for this reason, the particles can settle out over time. Examples of suspensions include house paint, silty river water, and sand in water. A suspension may scatter light, or the suspension may be opaque.
Heterogeneous mixtures vs. homogeneous mixtures
Heterogeneous mixtures contrast with homogeneous mixtures. A homogeneous mixture is a mixture in which all components are uniformly distributed, and all samples appear the same. Heterogeneous mixtures may contain a homogenous mixture as one of its phases.
Consider a bowl of chicken noodle soup, a heterogeneous mixture. The phases in the soup are broth, chicken, noodles, and carrots. The broth is a homogenous mixture; each spoonful of the broth alone is the same.
Examples of homogeneous mixtures are air, saltwater, most alloys (like brass or steel), and vinegar (acetic acid and water).
Heterogeneous mixture quiz
To check your understanding, answer these questions, and then compare your answers to ours below.
What does the word “heterogeneous” mean in physical science and chemistry?
Is dirt a heterogeneous mixture?
If a mixture contains items in different phases of matter, is it heterogeneous or homogeneous?
Please give one example each of each of a solid, liquid, and gaseous heterogeneous mixture.
What are the two main distinguishing features between colloids and suspensions?
How did you do? Check your work against our answers.
The word “heterogeneous” used in physical science and chemistry means a non-uniform mixture with visible, individual items or particles.
Dirt is a heterogeneous mixture. Dirt and soil are made from different particles like minerals, water, living organisms, and other organic matter.
A mixture containing items in different phases of matter is heterogeneous.
One example of each a solid, liquid, and gaseous heterogeneous mixtures could be concrete, seawater, and smog.
The two main distinguishing features between colloids and suspensions are their particle size (colloids have smaller particles; suspensions have larger particles) and the settling out of particles, which occurs only in a suspension.