Mixtures & Solutions

Essential Questions What is a mixture? What is a solution? What is the difference between a mixture and a solution? How can materials in a mixture or solution be separated?

How many of you like trail mix? In this trail mix you will see M&M’s, chocolate chips, raisins, & nuts. If you like ONLY M&M’s, you can pick out just the M&M’s. All of these ingredients can be separated easily using purely physical means – which makes it a MIXTURE.

Mixtures Look at this salad- what makes this salad a mixture? A mixture is two or more materials that are combined without changing any of them. Look at this salad- what makes this salad a mixture? You can separate all the ingredients: Tomatoes, cucumbers, onions, lettuce, and bean sprouts- and its still a salad.

Mixtures The substances in a mixture usually keep most or all of its own characteristics. Items used in a mixture can be separated using physical methods. Like in a pizza, if you don’t like pepperoni- you can pick them off- but it’s still a pizza! You could use a filter to separate sand and water. Using more scientific examples, you could use a magnet to pull iron filings out of a mixture of iron filings and salt.

There are many kinds of mixtures. A solid with a solid. You can mix two solids together. Rocks (solid) in sand (solid). A solid with a liquid. You could mix a solid with a liquid. Sand (solid) in water (liquid). Liquid with liquid or gas. Liquid can also be mixed. You can mix water (liquid) & salad oil (liquid). Soda drinks are mixtures of liquid and gas Gas mixtures. Even gases can be mixed. Air is oxygen, nitrogen, carbon dioxide, and other gases.

Mixtures Everything can be separated into different parts. This is what makes it a mixture.

Solutions Now that you have an understanding of what a mixture is, lets move on to solutions.

Solutions A solution is a special type of mixture. In a solution, one substance dissolves into another. It spreads evenly throughout the mixture. Not every mixture is a solution. Only some things can dissolve in others. When something will not dissolve, you can still see it.

Solutions Think what happens when a spoon of sugar is stirred in a glass of hot water. The sugar seems to disappear into the water. Where does the sugar go? It actually breaks down into tiny particles. These sugar particles are surrounded by water particles (molecules). That is why the sugar seems to “disappear.”

Solutions In a solution, the ingredients may change some of their properties and keep others. The sugar that dissolved in the water no longer looks like white crystals, but the solution still tastes sweet from the sugar.

Solutions It is harder to separate the ingredients of a solution than other mixtures. The best way to separate them is often to boil or evaporate the liquid.

Remember, In a mixture- substances can be separated- Solutions can not! http://www.harcourtschool.com/activity/mixture/mixture.html http://www.bbc.co.uk/schools/ks2bitesize/science/materials /reversible_irreversible_changes/play.shtml (physical and chemical changes – read

if you added sand to water? Would it dissolve? What Would Happen… if you added sand to water? Would it dissolve? No- Sand does not dissolve in water rather the particles fall to the bottom of the container. Sand in water is NOT a solution.

Solubility Solubility is the measure of how well one substance dissolves in another. Ex. Salad Dressing- As you’ve already learned, oil and water cannot dissolve in each other. Oil is not soluble in water. Same with sand- Sand is not soluble in water therefore the solubility is zero!

Examples of Mixtures and Solutions Mixtures-mud, latex paint, cake batter, vinaigrette salad dressing, milk, foam (bubble bath), blacktop, concrete Solutions-Kool-aid, seawater, vinegar, antifreeze, gasoline, metal alloys like steel, brass, and bronze.

Let’s Review Which of these is a mixture? A. Apple B. Broccoli C. Ham sandwich D. Carrot stick C.

Let’s Review Which of these is a mixture? A. Pail of sand and soil B. Copper wire C. Ring of pure gold D. Pinch of salt A.

Let’s Review Which of these is an example of a solution? Granola B. Iced tea C. Pizza D. Salad B.

Name a substance besides sand and oil that are not soluble in water. Let’s Review Name a substance besides sand and oil that are not soluble in water.

Using a Venn Diagram, compare and contrast mixtures and solutions. Let’s Review Using a Venn Diagram, compare and contrast mixtures and solutions. Mixtures Solutions