Chapter 2-1
A substance made up of two or more different types of atoms bonded together. Elements are to compounds as letters are to words. Elements change when they form compounds. Sounds of letters change to form words
All compounds have the same ratio of elements. Ammonia: 3 hydrogen for every nitrogen Ratio of 3:1 Hydrazoic acid: 1 hydrogen for 3 nitrogen atoms Ratio of 1:3 Different ratios = different properties
A chemical formula uses chemical symbols and the ratios of elements to represent a compound. Carbon Dioxide: 1 carbon and 2 oxygen Symbol for Carbon CC Symbol for Oxygen O CO 2 Subscript: Number to the lower right, tells the number of atoms
Hydrogen Chloride: 1 hydrogen and 1 chlorine Water: 2 Hydrogen and 1 Oxygen Ammonia: 1 Nitrogen and 3 Hydrogen CH 4 C3H8C3H8
Hydrogen Chloride: 1 hydrogen and 1 chlorine HCl Water: 2 Hydrogen and 1 Oxygen H2OH2O Ammonia: 1 Nitrogen and 3 Hydrogen NH 3 CH 4 Methane: 1 Carbon and 4 Hydrogen C3H8C3H8 Propane: 3 Carbon and 8 Hydrogen
Page 45 numbers 1, 2, 4 and 6.