Class_2_Jan_16 - but something in between: a. Dust is a...

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CHEM 001 Class 2 Class Notes January 16, 2008 C. Cecil Cuppett, Ph.D. Chapter 1: 1. The terms compound and molecule are almost the same. Molecules and compounds are a collection of at least two atoms that are bound together. In some cases, the substances are better described as ions instead of molecules (this will be explained later in the course). 2. Diatomic molecules have just two atoms bound together. Examples are these gases: O 2 , N 2 , Cl 2 , CO. 3. The molecular formula describes the exact ratio of the atoms in a molecule (compound). The subscripts show how many atoms of each type are in the molecule. For example, H 2 O (water), H 2 O 2 (hydrogen peroxide), C 6 H 12 O 6 (glucose), CO 2 (carbon dioxide), CH 4 (methane). 4. An important group of substances are colloids. These materials are not exactly solids, liquids or gases
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Unformatted text preview: but something in between: a. Dust is a solid finely dispersed in a gas (air) b. Fog is a liquid finely dispersed in a gas (air) c. Shaving foam is a gas finely dispersed in a liquid d. (See more examples of various types of colloids on page 13 of your text.) 5. Colloids may separate into the components that makeup the colloid in which case the colloid is not a true solution but actually would be a dispersion. In other cases the colloid is very stable and may be considered a type of solution. 6. Gases follow a relationship as follows: PV = nRT where P = pressure, V = volume and T = temperature. n and R are numerical constants usually....
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This note was uploaded on 03/18/2008 for the course CHEM 001 taught by Professor Cuppettc during the Spring '08 term at Pennsylvania State University, University Park.

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