Chem notes - 1/22/08 CHEM 211 Chemistry the study of matter...

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1/22/08 CHEM 211 Chemistry the study of matter * Matter is anything that exists solid liguid or gaseous state Subdivided into 3 types: 1. elements simplist fundamental unit of a substance that can exist there 92 elements that exist naturally on earth 2. compounds 2 or more elements in a definite ratio by weight H2O compound of H2O2 a compound has none of the characteristics of the elements of which it is composed 3. mixture no definite ratio, variable concentration of the substance. Ex. Cake mix 20.9% O2 in the air 15% not enough to survive 25% combustion Iron contracted O2 Fe+O2 Fe2O3 Composition of a common mixture—the ocean one cubic mile of the ocean water contains: 81 mil. Tons of chlorine 43 mil tons of sodium 5.6 mil tons magnesium commercial 280 thos tons bromine commercial 200 tons of iodine 2 tons of uranium 57 pounds of gold .5 grams of radium kills bone marrow which causes leukemia Physical Properties and changes (observable): Color, odor and taste Density d= mass/volume (can be in any unit) Viscosity Boiling and freezing point Solid, liquid or gas Phy. Change is a change that does not result in the formation of a new substance. Boiling/freezing of water or other liquids Graphite to diamonds is a change in structure only C(graphite)+heat+pressure C(diamonds) Therefore what about the stability of diamonds at room temp and atmospheric pressure. --graphite hexagonal; diamond tetrahethral (shape is the only thing that changes.)
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1/27/09 Chemical Properties and Changes Chemical prop are those pro that describe a chemical change Chem. changes result in the formation of new substances that do not have any of the chem. characteristics of the reaction o 2H2+O2+energy(fire, spark) 2H2O Note subscripts of hydrogen and oxygen Elements 1,7,8,9,17,35 and 53 are diatonic Number in front of element or compound are b/c of a fundamental lat of chemistry: matter is neither created nor destroyed – in plain English matter is just rearranged Metric System: Deci 1/10; Centi 1/100; milli 1/1000; kilo 1000 Length: 2.5cm-1 inch Standard Unit (SU) Meter Mass: 454 gram – 1 lb; 29 gram- 1 ounce SU gram Volume: 1 L- 1.06 quarts; 29 mil- 1 fl ounce SU Liter Temperature: C F F=9/5C+32 F frez: 32 boil: 212 dif 180 (9/5=180/100) F C C=5/9(F-32) C frez: 0 boil: 100 dif 100 C K K=C+273 Kelvin only for gases heat 1 degree expands 1/273 of volume o 273 expansion/ contraction of gas The Atmosphere as a mixture and the greenhouse affect: 95% of the green house effect is due to H2O vapor and 99.999% of it is natural in origin 5% of the green house effect is due to CO2, CH4 and NOx with CO2 being the most prevalent (99.4% by volume of the 5%) the other gases trap more heat CO2 is responsible for 3.6% of the 5% About 97% of the atmospheric CH2 content is natural in origin. We contribute about 3% o This means that .11% of the green house effect (3% of 3.6%) is due to human release of CO2 o 99.89% of the green house effect has nothing to do with CO2 release from
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This note was uploaded on 04/29/2009 for the course CHEM 211 taught by Professor Papanastasiou during the Spring '07 term at George Mason.

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Chem notes - 1/22/08 CHEM 211 Chemistry the study of matter...

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