Sci 200 Questions With Complete Solutions

Power = ?? - Energy / Time Which of the following is not a unit of energy? kg * m2/s2 N*m Joules BTU kg * m2/s - kg * m2/s Conservation of Mass - Mass can neither be created nor destroyed, but simply changed from one form to another. First Law of Thermodynamics - The total amount of energy in nature is constant. Second Law of Thermodynamics - Efficiency = (Q2 + Q1) / Q2 Q1 (heat absorbed at the higher temperature, T ) Q2 (heat released at lower temperature, T ) Conservation of Energy - The total amount of energy in nature is constant. Heat of Combustion - Enthalpy change when organic compounds containing C, H or O are burnt in oxygen to yield only CO2 and H2O Heat of Hydrogenation - The change in heat content when 1 mole of unsaturated hydrocarbon is converted to the saturated compound by gaseous hydrogen. Heat of Reaction - The ______ can be calculated by taking the difference in the heats of formation of products and reactants. Hess' Law - The heat change in a chemical reaction is the same if it takes place in one step or several. Trend of entropy - The total amount of entropy in Nature is increasing. Which fuel generates the least grams of CO2 per kWh of chemical energy? - Natural gas (190) What are the four steps that prepare a resource for end use? - Extraction, upgrading, conversion, application Energy Technology Perspectives Model - Steps to convert primary energy to useful energy Steps in the Energy Technology Perspectives Model - Primary energy, conversion sectors/process, final energy, demand sectors/process, useful energy Best type of energy for stationary applications - Electricity Best type of energy for mobile applications - Liquid fuels (gasoline/diesel) Types of cost in an energy project - Capital costs (initial and ongoing), fixed operating costs, variable costs Discount Factor (formula) - (1+i)^n Factors affecting energy availability and use - Technical, financial, customer acceptance, political Types of renewable energy - Wind (off and on shore), solar, hydroelectricity, waves, tides, geothermal Types of solar energy - Thermal, photovoltaic, biomass, food Energy Unit E (per day) - kWh/d Energy Heating & Cooling(formula) - heat capacity J/(LC) * 多少升水 L * 温度差 C = MJ * 1 KWh /3.6 MJ = ??kWh Energy(light) per person (formula) - E_{light} = (sum(Pi * Ti)) / p Energy (wind) (formula) - Kinetic Energy = 1/2 mv^2 = 1/2(density*area*vt)v^2 = 1/2 * density (kg/m3) * area * time * (velocity)^3 Power (wind) (formula) - Power = Kinetic Energy / t = 0.5 * density * area * (velocity)^3 Power generated by a single wind mill (formula) - EfficiencyFactor * Power/unitArea * area(turbine-circle) = Efficiency factor * 1/2 density*v^3 (drop A because its per unit area) * pi *r^2 Power generated by the whole windmill - Power per windmill / land area per windmill(its a square-area is 边长平方） Betz's Law - The maximum efficiency of wind mill is 59.3% and occurs when the departing air is 1/3 the incoming air critical speed 5x diameter of the turbine - Minimum distance between windmills W/m2 of direct sunshine on equator - 1000 W/m2 Power Latitude (Solar) Formula - P_latitude = P_equator * cos(90-latitude) Unit: W/m^2