All About Solutions

Contributor: Hannah Brooks. Lesson ID: 12915

You probably know that magnets have polarity, but did you know other substances have polarity? That's why you can't mix oil and water. Compound your knowledge of solutions right in your own kitchen!

categories

Chemistry

subject
Science
learning style
Visual
personality style
Lion
Grade Level
High School (9-12)
Lesson Type
Quick Query

Lesson Plan - Get It!

Audio:

Do you like to take things apart? Can you take apart your favorite soda?

Sodas are homogenous mixtures, because the components are mixed uniformly throughout the drink.

The carbonation is evenly distributed along with the sugar, making it hard to separate out each part of the drink.

Before continuing, if you missed or need to review the previous lesson in our Mixtures and Solutions series, find it under Related Lessons in the right-hand sidebar.

Solutions can exist as solids, liquids, and gases. In every solution, there is a solvent and a solute. The solvent is the substance that dissolves the solute. The solute is added to the solvent, and is dissolved into the solution. When making sugar water, sugar would be the solute and water would be the solvent.

mixture

  • Did you know that water is considered the universal solvent? It has earned that nickname because it is able to dissolve so many other substances! It cannot dissolve everything, though!

In chemistry, there is a saying to help you remember how things dissolve: "Like dissolves like." This does not mean that solids only dissolve solids, but it is based on the polarity of the substances involved in creating the solution.

As you watch a short video from Sonya Birazian, Bonding-polar vs nonpolar molecules -keeping it simple, to learn more about how this property influences compounds, copy and complete the graphic organizer below:

Polar Both Non-polar
     
     
     

 

 

Polar compounds can dissolve other polar compounds. Non-polar compounds cannot dissolve polar compounds. This is one reason that water cannot dissolve grease off of a dirty plate, but dish soap is able to dissolve it.

grease

The polarity of the solvent and solute should be considered when making a solution because you cannot force materials to dissolve one another. Have you ever tried to dissolve oil into water? It will not dissolve, because they do not have the same polarity. They remain forever separate.

oil

If the substance can dissolve into the solvent, it is considered soluble. The solubility is based on the chemical make-up, but also the concentration (or amount) of the solute and solvent. Even if a substance is soluble, it might not dissolve right away. Some materials dissolve instantly, like an Alka-Seltzer tablet, while other substances can take a lot longer, like time-released medications.

In order to make a solution, you must have a solute to dissolve, and a solvent to carry out the process of dissolving. Solutions can be made from any phase, sometimes even a combination of two phases. In order for a substance to be soluble, it must have similar polarity to the solvent. Water is very polar, making it the universal solvent. Non-polar substances can only dissolve other non-polar materials, thus proving the statement, "Like dissolves like."

In the Got It? section, you will learn more about molecular polarity.

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