Chem 1100 Lecture 9Outline of Last Lecture I. Carbon DioxideII. Weighing CarbonIII. Chemical EquationsOutline of Current Lecture I. StoichiometryII. Other Greenhouse GasesIII. Effects of Greenhouse GasesIV. Energy, Work, & HeatCurrent LectureI. Stoichiometrya. Stepsi. Balance the chemical equationii. Convert grams of known substances into molesiii. Use coefficients – calculate the number of moles unknowniv. Convert moles into gramsb. Methanol burns in airi. 2CH3OH + 3O2  2CO2 + 4H20ii. If 209 g of methanol are used up in the combustion what mass of water isproduced?iii. Grams CH3OH moles CH3OH  moles H2O  grams H2Oiv.=235 G H2OII. Other Greenhouse Gases: Methane (Ch4)1. Some global warming may be due to elevated levels of methaneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. Currently 1.8 parts per million ppm (2000) around 1% increase peryear3. Sources: fossil fuels, agriculture, biological decay4. Agriculture: plants get decayed, methane is created5. Nitrous Oxide (N2O – laughing gas)a. Dinitrogen Monoxideb. Slow increase over past 10 years. Increases about .31 ppm.c. Sources: fertilizers and deforestationd. Leads to ozone depletione. Soil and Ch4 react with N2o  ozone  photochemical smog6. Gathering Evidencea. Some factors not understood (sunspots, weather patterns, volcanoes)b. Atmospheric variations, inter-related variables (can’t isolate), data difficult to interpretc. Currently using computer modeling: take in a bunch of numbers all at once. It’s important to understand model limits. How do we know if a model works? Test it.d. Computer models: accurate in predicting global temperature changes, agree that the temperature is rising,the disagreement on the impact increase (0.5 degrees Celsius over the last century)III. Effects of Greenhouse Gasesa. Ecosystems: glacier/ice cap retreats, coral reef damagei. Disease spread? Malaria? The mosquito’s indigenous to this area don’t carry malaria but if the temperatures rise enough Missouri could become tropical and then malaria carrying mosquitos could live here. ii. Sea levels – 10-20 cm since 1900iii. Severe weather extremesb. What can we do? – Gather date/monitor it. Reduce fossil fuel dependence. Re-forestation. Better disposal/use of Co2. c. Ozone Hole Vs Global WarmingO3 CO2 CH4UV IRMontreal Agreement Kyoto Protocol(US did sign) (Us did not sign)d. Energy from CombustionIV. Energy, work, & heata. Work: movement of an object over a distancei. Heat: energy that goes hot  coldii. Temp: amount of heat energy in an objectiii. Determines direction that the heat energy is going to flowiv. The hot one will cool off and the cool one will warm upb. Measurement of molecular motion. The molecules of that object will move around more and more when you heat it up. When you cool it down the molecules slow down enough that they form solid ice.i. Amount of heat in an objectii. 200 mL beaker and a 100 mL beaker – the molecules move at the same speed but the 200 has 2x the molecules. So the 200 mL container has 2x the heat! 2x the energy to heat up the larger.iii. Heat in an object depends on temperature, mass, & material. Some materials absorb heat better than others. So we want to think about the amount of heat in an object.iv. Units of Energy: Joule (J) is roughly about enough energy to get a human heart to beat one time. The technical definition is enough energy to take 1 kilogram weight to raise it a height of 10 cm. v. Calorie (cal) – raise temp of water by 1 degree celcious = 4.184 Jvi. Calorie = 1000 calories = 1 kilocalorie = label info on foodc. Energy Transformation – Thermodynamics: How heat movesi. First law of thermodynamics: energy is neither created or destroyed (the law of conservation of energy)ii. Energy sources ARE consumed! When you burn gasoline in your car that energy is consumed.iii. Energy sources: breaking and creating chemical bonds.iv. What forms can energy take? – potential energy (chemical bonds)v. Arrangement of atoms, molecular structure, fossil fuels & foods, burning heatvi. Energy forms continued – heat can be transformed into mechanical energy such as steam/gasoline enginesvii. It can do work like with an electric motor (mechanical  electrical generators)viii. It can do work such as heating and lighting thingsix. Energy is not created or destroyed but there are some forms that are more useful than others.x. Efficiency: how much heat energy do you have to start with? And how much can you use to do work?-Can’t be 100% in the real world. There’s always some heat loss. Due to friction or lack of insolation.- A power plant that is 35% efficient is about as good as they can get. Only35% is converted to work to turn the turbine and 65% is lost as heat. i. Energy: Potential, Kinetic, Thermal (potential energy PE)ii. We are concerned with energy going to work.iii. The 2nd law of thermodynamics: heat  work (100% efficiency): impossible iv. Energy  workv. Heat wont flow cold to hotvi. Entropy (randomness) vii. Fuel sources to bonds1. Good energy sources: wood, oil, coal2. Nobody burns dirt3. Why are some fuels better?4. Combustion: rapid combination with O2 as a result you get heat. PE of reactants must be greater than PE of products. Otherwise there is no reaction. Difference is given off as