1. Section 2.3 Classifying Matter 1.To learn to distinguish between mixtures and pure substances 2.To learn two methods of separating mixtures Objectives

2. Section 2.3 Classifying Matter A. Mixtures and Pure Substances Matter can be classified as a mixture or a pure substance. AlloysAlloys are mixtures with metallic properties.

3. Section 2.3 Classifying Matter A. Mixtures and Pure Substances Mixtures –A mixture has variable composition A homogeneous mixture has the same properties throughout. (Kool-Aid) A heterogeneous mixture has different properties in different parts of the mixture. (Chocolate chip cookie)

4. Section 2.3 Classifying Matter A. Mixtures and Pure Substances Pure Substances A pure substance always has the same composition. Pure substances are of two types: –Elements –Elements which cannot be broken down chemically into simpler substances –Compounds –Compounds which can be chemically broken down into elements Water is a compound. All the components are the same—H 2 O molecules.

5. Science or Fiction Diamonds are the hardest compound found in nature. Diamonds are actually crystals of pure carbon and are the hardest known elemental form found in nature.

6. Science or Fiction Carbon exists in many elemental forms, including one called buckyballs. Carbon atoms make many complex spheres and tubes that are called fullerenes. The most famous of these molecules is the 60 carbon sphere that was named ‘buckyball’ after Richard Buckminster Fuller, who designed many geodesic domes, like the one called ‘Spaceship Earth’ in Disney World.

7. Science or Fiction Water is a good conductor of electricity. Pure water is a very poor conductor, but you rarely encounter pure water in your daily life. Water usually has many dissolved ions in it, and those ions are good conductors, so you should be very careful using electric appliances near water.

8. Section 2.3 Classifying Matter B. Separation of Mixtures Mixtures can be separated into pure substances by various means. Distillation (using boiling points to separate components)

9. Section 2.3 Classifying Matter B. Separation of Mixtures Mixtures can be separated into pure substances by various means. Filtration (using size of pieces to separate components) Filters are like screen doors. Things smaller than the pores (holes) can get through, things that are larger get stopped.

10. Section 2.3 Classifying Matter Summary: The Organization of Matter