CF - Substances and Mixtures Microlesson

Substances and Mixtures

Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. A mixture is composed of different types of atoms or molecules that are not chemically bonded.  

Quick Glance: Classifying Matter

Now that you have learned some of the basic principles of Food Chemistry, we are going to start classifying matter. 

Scientist classify matter into three areas- Gases, solids and liquids  

Of these three areas, an element is either a pure substance or a mixture. In the lesson ahead, the chart below gives you an overview of these two categories. Both substances and mixtures play a vital role in how we experience and use the energy from food.

 

Explore: Mixtures and Solutions

Now that you have a better understanding of matter and its physical properties. Let’s look at mixtures and solutions. These items are quite important in the science arena.

Solutions

Solutions are a homogenous mixture formed by the dissolution of a liquid, solid, or gas in a liquid. Solutions are made of solute (the substance being dissolved) and a solvent (the substance that does not dissolve) and are not easily separated. An example is salt and water mixed together. 

Mixtures

A mixture is any combination of two or more substances. These items can look the same when mixed together or they can look totally different. Many times, these items can be separated back out to their original form. When mixed, the components of the ingredients are not changed. Can be made with solids, liquids, or gases.

In a heterogeneous mixture,  the substances are not evenly distributed  

• Components are distinct and can be seen
• Not uniform in size
• May vary throughout the mixture

Example- chocolate chip cookie, pizza, Chex mix, oil & water

Use the presentation below to learn about the types of Heterogenous Mixtures.

 

So What Is The Difference Between A Mixture And A Solution?

• Matter can be broken down into two categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components.
• A chemical substance is composed of one type of atom or molecule.
• A mixture is composed of different types of atoms or molecules that are not chemically bonded.

 

Watch the video below to learn the difference between substances and mixtures.  

 

As mentioned before, some scientists and chemists have studied mixtures for centuries. Experiments are performed to correctly classify each item. Scientists have found ways to separate these mixtures. There are several ways that this can be performed.

Take a look at the tabs below to learn more about ways to separate mixtures.

Various separation techniques exist in order to separate matter, including distillation, filtration, evaporation and chromatography. Matter can be in the same phase or in two different phases for this separation to take place.

 

Mixtures have their place in Food Chemistry but solutions play a role as well. A solution is a homogenous  mixture formed by the dissolution of a liquid, solid or gas in a liquid. Solutions are made of solutes and solvents. They are not easily separated.

1. Solute- The substance that dissolves
2. Solvent- The substance that does not dissolve

 

Or, another method of defining solvent and solute is to say that the component of the solution present in the largest amount is the solvent while the components present in lesser amounts are the solute. In a homogenous solution, all the substances are evenly distributed throughout the mixture. These items are mixed at the atomic or molecular level. All mixtures have the same properties. These can’t be separated by physical means. A great example of this is salt and water. Two others that come to mind that are quite common are the air we breathe and the blood running through our veins. Those two vital items are a solution.

Challenge

So do you think you understand substances and mixtures? Try the challenge below to test your knowledge. Drag each item to the correct category. 

Takeaway: What Is Your Takeaway?

What's the Tyndall Effect?  

Ever wondered how to know if a solution is a colloid? One of the best ways to tell is by using the Tyndall effect method. The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible. Particles must be in the range of 1-1000 nanometers in diameter for a solution to be classified as a colloid. This theory was proven in the 19^th  century by physicist John Tyndall. 

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