Mixtures

Lesson Plan - Get It!

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Fruit salads contain different fruits, like strawberries, bananas, blueberries, and grapes.

These fruits can be cut into different size pieces but are easily identified as part of the salad. Fruit salads are a good representation of a mixture.

In chemistry, mixtures are physically mixed substances. Generally, mixtures can be separated into the components that make them up.

For example, you could separate all the fruit in a salad by type.

There are two types of mixtures: heterogeneous and homogeneous.

A heterogeneous mixture is similar to the fruit salad example because it is easy to identify the materials in the mixture. A heterogeneous mixture may include all three phases of matter: solids, liquids, and gases.

A smoothie has solid and liquid materials, making it a heterogeneous mixture.

It is also an example of a suspension because the substances will settle out over time. The heavier, larger particles will sink to the bottom while the liquid concentrates at the top.

In a homogeneous mixture, the substances are uniformly mixed. That means it is tough to tell individual components apart.

Think about making Kool-Aid. You cannot identify individual substances once you have mixed the powder, water, and sugar.

Another name for homogeneous mixtures is solutions. Solutions are made up of mixed materials, making individual components invisible.

Solutions include soda, laundry detergent, and mouthwash. These examples are mixed so that you cannot identify individual parts!

• Did you know that jello and milk are also solutions?

They illustrate a special type of solution called a colloid. A colloid has larger particles than a liquid solution, but the materials are mixed in the same uniform way as a liquid solution.

Not every substance is found in a mixture; some are considered pure.

Elements and compounds are pure substances because they cannot be isolated into components. Compounds exist in nature with set ratios between the elements.

For example, sodium chloride will always have one sodium and one chlorine atom. It cannot exist with any other ratio.

Pure substances and mixtures make up many of the food items we consume, the products we use to prepare in the morning, and the chemicals that provide us with resources.

Pure substances comprise all the elements on the periodic table and compounds chemically bonded together.

Mixtures are physically combined and can exist as heterogeneous or homogeneous, based on the composition.

A heterogeneous mixture has easily identifiable parts, while a homogeneous mixture comprises uniformly blended materials. Another name for a homogeneous mixture is solution.

Continue to the Got It? section to learn about separating the components in a mixture.