What is a solution?

1. What is a solution?

2. Vocabulary • Heterogeneous Mixture • Homogeneous Mixture • Precipitate • Solute • Solution • Solvent • Substance

3. Write the following in your science notebook: Use Your Noodle! Think About It: Do you add sugar to your tea? How do you know that the white substance will make your drink sweeter?

4. What are atoms, elements, and substances? • Atoms – Basic building block of matter • Each has its own chemical and physical properties • These properties are determined by the number of protons the atom has • Elements – A pure substance • Cannot be broken down into simpler substances. • The number of protons in an element cannot change unless the element changes

5. What are atoms, elements, and substances? • Substances- Matter that has the same fixed makeup and properties throughout. • Cannot be broken down into simpler parts by physical process. • Example – water • Can freeze, boil, stir and filter water, but it is still water • Only way to change a substance is by chemical process.

6. Substances • Water, salt water and pulpy orange juice are all different liquids. • Differences are explained by chemistry • Example – Water • Can be frozen, melted or boiled • Is still water

7. Substances • Salt water • What happens when you boil salt water? • The water turns into a gas and leaves salt behind. • Pulpy orange juice • What happens when you strain orange juice? • It looses it’s pulp but it is still orange juice. • How does chemistry explain these differences? • Has to do with the chemical makeup of these materials

8. Examples of Physical and Chemical Processes

9. Write the following in your Science Notebook: Use Your Noodle! #1 Explain: How do physical processes differ from chemical processes? You have 3 MINUTES!

10. What are compounds? • Compound – A substance made of two or more elements that are chemically combined. • Example – Water • The makeup of a compound is always the same • Example – water molecule always has two H atoms combined with one O atom • All water, whether frozen, liquid, or vapor has the same ratio of H atoms to O atoms.

11. Write the following in your Science Notebook: Use Your Noodle! #2 Classify: Why is water a compound and not an element? You have 2 MINUTES!

12. Mixtures • Imagine drinking a glass of salt water. • You’d know right away it wasn’t pure water • Salt water is not a pure substance • It is a mixture of salt and water • Mixtures – are made when two or more substances come together but do not chemically bond together to make a new substance • Can be separated • Example – boil salt water and you can separate the two

13. Mixtures • Mixtures do not contain an exact amount of each substance like a compound. • Example – Lemonade can be strong or weak tasting • Depends on how much lemon juice is added to the water • Can also be sweet or sour, depending on how much sugar is added. • No matter how strong, weak, sweet or sour, it is still lemonade.

14. What are heterogeneous mixtures? • Some mixtures are easy to see • Example – Watermelon • Mixture of fruit and seeds but are not mixed evenly • Heterogeneous mixture – a mixture where the substances are not mixed evenly • Usually easy to tell apart • Example – Bowl of cereal with milk

15. What are homogeneous mixtures? • When you mix sugar and water together you don’t see the sugar particles floating in the water • Homogeneous mixture – two or more substances in which the molecules mix evenly but do not bond together • Another name for a homogeneous mixture is a Solution

16. Write the following in your Science Notebook: Use Your Noodle! #3 How would you describe the sugar and water molecules in a solution of sugar water? Not mixed evenly Combined Mixed evenly Compounded You have 1 MINUTE!

17. How Solutions Form • When you mix sugar and water together, you can’t see the sugar particles in the water. • The sugar doesn’t actually disappear. • Sugar molecules spread out until they are evenly spaced throughout the water molecules, forming a solution • This is called dissolving

18. Dissolving Solute Solvent • The substance in a solution that dissolves or seems to disappear, is called the Solute • The substance that dissolves the solute in a solution is the Solvent

19. How can solids form from solutions? • Sometimes a solute can come back out of a solution and form a solid. • This process is called Crystallization

20. Crystallization • Happens because of a physical change • Example – when a solution is cooled • Can also happen when some of the solvent evaporates • A stalactite in a cave is an example of crystallization • Minerals dissolve in water as it flows through rocks • When the solution drips from the ceiling of the cave, some of the water evaporates • Minerals crystallize to form the stalactite.

22. Write the following in your Science Notebook: Use Your Noodle! #4 Apply: Minerals dissolve in water as it flows through rocks at the top of the cave. In this solution, what is the solute and what is the solvent? You have 3 MINUTES!

23. Precipitate Formation • When some solutions are mixed, a chemical change happens and a solid forms. • Precipitate – a solid that forms when solutions are mixed and a chemical change happens • Compare and Contrast • A precipitate can form in a shower • Minerals are dissolved in water and can react chemically with soap. • Chemical reaction forms a precipitate called soap scum

24. Types of Solutions • Not all solutions are solid solutes dissolved in liquid solvents. • Solutions can be made up of combinations of solids, liquids, and gases

25. Write the following in your Science Notebook: Use Your Noodle! #5 Interpret Data: Name two solutions that have carbon dioxide as one of the solutes. You have 2 MINUTES!

26. Liquid Solutions • Sugar water and salt water are examples of solutions with liquid solvents and solid solutes. • The solute in a solution can be a solid, another liquid, or even an gas. • The state of the solution will usually be the same as the state of the solvent. • Example – Sugar is a solid and water is a liquid. • When mixed together they form a solution. • The solution is a liquid.

27. Write the following in your Science Notebook: Use Your Noodle! #6 Explain: What does the state of a solution usually depend on? You have 3 MINUTES!

28. What are liquid-gas solutions? • Carbonated drinks are examples of solutions with liquid solvents and gas solutes. • The gas solute is carbon dioxide. • Water is the liquid solvent • The CO2 gives the drinks their fizz.

29. What are liquid-liquid solutions? • Vinegar is an example of a liquid-liquid solution • Water is the liquid solvent and acetic acid is the liquid solute. • In vinegar, only 5 percent of the solution is acetic acid. • Water makes up 95 percent of the solution.

30. Gaseous solutions • Gas-gas solution - Sometimes, a small amount of one gas is dissolved in a larger amount of another gas. • The air you breath is a gaseous solution. • About 78% of air is N, which is a solvent • About 20% of air is O, which is one of the solutes • The other solutes in air are CO2, Ar and some other gases in small amounts.

31. Solid Solutions • In a solid solution, the solvent is solid • The solute can be a solid, liquid or gas. • The most common solid solutions are solid- solid solutions • Both the solvent and solute are solids. • Steel is a solution of C dissolved in Fe. • A solid-solid solution made from two or more metals is called an alloy. • Brass is an alloy of Zn dissolved in Cu

32. Write the following in your Science Notebook: Use Your Noodle! #7 Identify: What states can the solutes be in a solid solution? You have 2 MINUTES!

33. Fill out the graphic organizer with important facts about mixtures and solutions. Mixtures Review! Homogeneous Heterogeneous Description: Example: Description: Example: Solutions Description: