Today’s Starting Point 1. What is an intensive property of matter? List two examples of intensive properties.   2. What is an extensive property of matter? List two examples of extensive properties. Do not depend upon the amount of matter present; color, density Do depend upon the amount of matter present; mass, volume

Today’s Starting Point 3. Compare these two elephants. What would be an intensive property of the elephants? What would be an extensive property of the elephants?

Pure Substances and Mixtures

By the end of the class period today I will be able to… Identify a piece of matter as an element, compound, homogeneous, or heterogeneous mixture based upon its properties

Pure Substances Composition is the same throughout and does not vary from sample to sample. CANNOT be broken down by physical changes Can be an element or compound.

Element Definition: substances in their simplest forms Cannot be broken down by a physical or chemical change Found on the periodic table Made up of one type of atom

Examples of Elements: Hydrogen Carbon Lithium Gold What are two other examples of elements not listed above? What do all elements have in common?

Compound Definition: substance formed by the chemical combination of two or more elements can be broken into simpler substances by a chemical change + = Compound

Law of Definite Proportions A compound is always composed of the same elements in the same proportions. In other words, Carbon Dioxide (CO2) is always composed of 1 atom of C and 2 atoms of O. If there are different amounts of carbon or oxygen, it is no longer carbon dioxide.

More Examples of Compounds

Mixture Definition: two or more pure substances (elements or compounds) that are mixed together but NOT joined chemically NOT a pure substance Examples: The air we breath, gasoline for cars, the sidewalk on which we walk

Homogeneous Mixtures Uniform in composition and appearance Same proportion of components throughout Consists of two or more substances in the same phase Also called solutions

Heterogeneous Mixtures variable appearance and composition

Raise ‘em Up! Look at the following example and with your partner determine if it is a heterogeneous mixture, homogeneous mixture, element, or compound Chicken noodle soup Strawberry banana smoothie Coca-cola Purified water Helium

Heterogeneous Mixture Chicken Noodle Soup Heterogeneous Mixture

Pure Water Compound

Tap Water Homogeneous Mixture

Pure Gold Element

Coca-Cola Homogeneous Mixture

Kool Aid has mass and takes up space

Can be separated by allowing water to evaporate

Same composition throughout