CHEM 106 Cheat Sheet for Final_Problem_Set_Solution

# CHEM 106 Cheat Sheet for Final_Problem_Set_Solution -...

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Prelim 1 (Wks 1-6) Significant Figures – Counting: 1. All nonzero digits are significant. 2. Zeroes to the left of the first nonzero digit are not significant. 3. Zeroes at the end of a number that includes a decimal point are significant. Addition and Subtraction: - the answer can contain no more decimal places than the least accurate measurement Multiplication and Division: - the answer can contain no more significant figures than the least accurate measurement Scientific Notation Addition and Subtraction – numbers converted to same power of 10, coefficients added or subtracted and exponent remains Multiplication – coefficients multiplied and exponents added Division – coefficients divided, exponent of divisor is subtracted from exponent of number being divided J.J. Thomson – cathode ray tubes – discovery of electrons Bohr’s View – there are 2n^2 electrons allowed in a level Modern View – orbitals that differ in shape and energy Filling of Orbitals: 1s→2s→2p→3s→3p→4s→3d→4p→5s→ 4d→5p→6s→4f (s=2, p=6, d=10, f=14) Trends -Size of atoms decreases as you move from left to right -Size of atoms increases as you move down a group -Reactivity for metals increases as you move down a group -Reactivity for nonmetals decreases as you move down a column Groups: 1A – Alkali, 2A – Alkali Earths – harder, more dense, 7A – Halogens – diatoms, 8A – Noble Gases – colorless, not reactive Electromagnetic Radiation: Λv = C , E=hv - Λ = wavelength, v = frequency, C = speed of light -As Λ decreases, v increases, E increases -As Λ increases, v decreases, E decreases -Troposphere – Tropopause (10 km) – Stratosphere (Ozone) – Mesosphere (temp decreases as you go higher in the troposphere, and then increases as you proceed through the stratosphere) - Anthropogenic pollution – attributable to human activity - Clean Air Act (1990) – regulates particulates, ozone, CO, nitrogen and sulfur oxides, ozone-depleting chemicals (freons) - Acid Rain – H 2 SO 4 (sulfuric acid) acidifies soil and ground water - Thermal Inversion –polluted cool air can’t rise above warm air Photochemical Smog – formed by action of sunlight on photoreactive pollutants in the air Photodissociation of nitrogen dioxide: NO 2 → NO + O, O 2 + O → O 3 (NO and NO2 are both pollutants) -RO 2 , NO 2 and aldehydes are in smog - Incomplete combustion – insufficient oxygen – creates CO Solutions to Smog and Ozone -Scrub sulfur dioxide from coal emissions, cars with better mileage, electric or hydrogen, fuel cells, catalytic converters (NO X to N 2 ), minimize volatile organic compounds - Rainout – pollutants in air removed by natural precipitation -Because a double bond is stronger than a 1.5 bond and requires more energy to break, oxygen molecules absorb higher-energy UV radiation (UV-C) – ozone absorbs lower energy (UV-B) – therefore, ozone is more reactive toward UV light than is oxygen. -Steady state – net rate of destruction = net rate of formation

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CHEM 106 Cheat Sheet for Final_Problem_Set_Solution -...

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