03-08-10-thermo1-preview.ppt

Today marks the beginning of the 2nd part of the course. Today: 5.1 ? 5.3 1st part of the course Kinetics Equilibrium Acid-base chemistry Review of CHM 116: Chemical Reactions Chemical laws (or principles) 2nd part of the course 1st law of thermodynamics 2nd law of thermodynamics The energy of the universe is always constant The entropy of the universe is always increasing Electrochemistry Review of CHM 116: Chemical Reactions ? S = ? + Heat Design chemical processes to obtain desired outcome. Practical: Design chemical processes to obtain desired outcome. Practical: Design chemical processes to obtain desired outcome. Practical: Design chemical processes to obtain desired outcome. Practical: Design chemical processes to obtain desired outcome. Practical: Steven Chu 12th United States Secretary of Energy Romantic: Discovery of chemical laws were to science what the romantic movement was to the arts. Design chemical processes to obtain desired outcome. Practical: Frederic ______ (1810 ? 1849) Sadi _______ (1796 ? 1832) Rudolph _______ (1822 ? 1888) J. Willard ______ (1839 ? 1903) Michael _______ (1791 ? 1867) ENERGY ??????? - energos, "active, working" Law: Conservation of Energy (1st law of Thermodynamics) Analogy from: Feynman?s Lectures on Physics, Vol. 1, Sec.4-1 No matter what Calvin does with the blocks, there are always 28 remaining ! Law: (Conservation of Calvin?s blocks) NO !! , do not open my toy box !! number of blocks seen (weight of box) ? 16 ounces 3 ounces = constant + (height of water) ? 6 inches 1/4 inch + + ? Energy: sometimes some of it leaves the system and goes away. sometimes some comes in. Large number of different forms: Gravitational energy Mechanical energy Thermal energy Elastic energy Electrical energy Chemical energy Radiant energy Nuclear energy Mass energy, etc? 6 CO2 + 6 H2O + chemical energy C6H12O6 + 6 O2 C6H12O6 + 6 O2 6 CO2 + 6 H2O + chemical energy radiant energy mechanical energy 1st Law of Thermodynamics Total energy of the universe is constant Also can be stated as: energy can be converted among types, but never created nor destroyed. Note: Energy available for human utility is not conserved so easily? Energy Units 1 Joule (J) = 1 (Kg m2)/ s2 Calorie = Heat required to raise temp. of 1g of H2O(l) from 14.5 °C to 15.5 °C (1 cal = 4.184 J) CLICKER question: Calorie Calor is how we say Heat in Spanish Heat versus Temperature Temperature: measure of the average microscopic kinetic energy and ability to transfer energy as heat. Heat: manner of energy transfer that results from a temperature difference between two systems (or system and surroundings). T1 T2 T1 T2 < T1 T2 T1 T2 < time = 0 Heat (q) Equilibrium temperature, T1 < Teq < T2 time > 0 Heat Flow Heat flows until ________________ is reached. At thermal equilibrium, all substances involved will have the same ___________. Microscopically, energy is still being transferred among individual atoms/molecules, but there is no net energy transfer (heat flow) at thermal equilibrium. Heat Transfer Specific Heat Capacity: amount of heat required to raise the temperature of 1 g of the substance by 1 K (or 1 °C) Water: CWater = 4.184 J / g.K Iron: CIron = 0.449 J / g.K CLICKER question: System vs. Surroundings Will need to define for each problem/question you deal with. Heat flow: Exothermic process: system ? surroundings Endothermic process: surroundings ? system Heat Gained or Lost When you warm or cool something, you can determine the change in temparature: ?Tsys = Tsys,final ? Tsys,initial Heat transferred: q = (mass) (?Tsys) (C) Heat transferred Heat Transfer between Systems qmetal = - qwater qwater = (mwater) (?Twater) (Cwater) qmetal = (mmetal) (?Tmetal) (Cmetal)