CHEM 1125Q 1st Edition Lecture 1 Outline of Current Lecture (Ch. 10)I. Energy Changes in Chemical ReactionsA. Energy and Energy Changes II. ThermochemistryIII. ThermodynamicsA. ThermodynamicsB. First Law of ThermodynamicsIV. States and State FunctionsV. Work and HeatA. HeatB. WorkVI. EnthalpyCurrent LectureI. Energy Changes in Chemical ReactionsA. Energy and Energy Changesa. There are three main components to a reaction: the system, the surroundings, and the universeb. The system is the main focus of a reaction that exists inside of the surroundingsc. The surroundings make up the rest of the universe outside of the system in focusII. ThermochemistryA. Thermochemistry is the study of heat in chemical reactionsa. Heat is the transfer of Thermal Energy and is measured in Joules (J)b. In a chemical reaction, heat is either absorbed by the system or released into the surroundingsc. The SI unit for energy is the Jouled. Energy can also be measured in caloriesi. 1 calorie = 4.184J ii. 1 Cal = 1000 caloriese. When heat is transferred from the system to the surroundings, it is an exothermic processThese 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.f. When heat is transferred from the surroundings into the system, it is an endothermic processIII. ThermodynamicsA. Thermodynamicsa. Thermodynamics deals with conversions between heat and other forms of energyb. There are 3 types of systems:i. Open = the system exchanges both mass and energy with the surroundingsii. Closed = the system allows energy transfer, but not mass transfer with the surroundingsiii. Isolated = the system does not exchange mass or energy with the surroundingsB. First Law of Thermodynamicsa. Energy cannot be created or destroyed, but instead is transformed into different forms of energyb. Δ Usystem + Δ Usurroundings = 0c. Δ U = change in internal energyd. The difference in energies of initial and final states is given by: Δ U = Uf – Uie. Δ Usystem = -Δ UsurroundingsIV. States and State FunctionsA. A system’s state, regardless of how that state was achieved, determines its propertiesa. A system’s initial and final states determine its magnitude of changeb. Areas of change include: Energy, Pressure, Volume, and TemperatureV. Work and HeatA. A system’s overall internal energy change is given by:Δ U = q + wB. Heata. Heat = qb. In an endothermic reaction, q is positivec. In an exothermic reaction, q is negativeC. Worka. Work = wb. When work is done on a system, w is positivec. When work is done by a system, w is negativeVI. EnthalpyA. Enthalpy is characterized by reactions that occur under either constant pressure or constant volumea. When volume remains constant, pressure
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