Transcript chp. 2
CHAPTER 2: MATTER What is matter? HOW ARE SAND AND GLASS RELATED? ARE THEY? At 1500oC sand becomes transparent and smooth like honey. A glass blower can use a hollow pipe to expand the soft and pliable sand. After the sand has cooled it has transformed into clear fragile glass. What has happened to the sand? The sand has gone through a chemical & physical change. The raw materials that make up sand are transformed into something new when heated at very high temperatures. *Key Concept* Chemistry helps us to realize how the differences in material properties relate to what the materials are made of. SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of matter. MATTER: ANYTHING THAT HAS MASS & OCCUPIES SPACE Examples of matter? Are light and sound examples of matter? No, because they have no mass or volume. An Element is a substance that cannot be broken down into simpler substances. Pure substances. Book, desk, air, etc. Ex. Carbon, Sodium, Oxygen Is salt an element? NaCl ATOMS Atoms are composed of protons (positive), electrons (negative), and neutrons (neutral). The nucleus of an atoms is made of _________ &___________. The _______________ of an atom are in constant motion around the nucleus. Atomic # : the number of __________ in an atom Atomic Mass: the number of ___________& __________. COMPOUND: A SUBSTANCE MADE OF ATOMS OF MORE THAN ONE ELEMENT BOUND TOGETHER Every compound is unique & different from the elements it contains. Ex. Hydrogen, oxygen, and nitrogen occur naturally as colorless gases but when combined they form Nylon which is a flexible solid. Atoms join together to create Molecules. Molecules may be composed of a single atom or more than one of the same atom. CHEMICAL FORMULAS A Chemical Formula: the chemical symbols & numbers indicating the atoms contained in the basic unit of substance Ex. C6 H12 O6 How many atoms of Carbon? How many atoms of Hydrogen? How many atoms of Oxygen? Numbers placed in front of the formula show the # of molecules 3 C6 H12 O6 Pure Substance vs. Mixture Pure substance: is matter with a fixed composition and definite properties. (can’t be broken down into parts) Water Mixture: a combination of more than one pure substance Compounds are different from the elements that make them Mixtures may have some properties similar to the pure substances that make them. Mixtures are classified by how thoroughly the substances mix Heterogeneous: substances are not uniformly mixed Homogeneous: mixing occurs between the individual unit & is the same throughout. No precipitate Miscible: describes 2 or more liquids that are able to dissolve into each other in various proportions Ex. Gasoline looks pure Immiscible: describes 2 or more liquids that do not mix into each other Ex. Oil & Water