PDF-Lecture 2: Enthalpy

1 149Reading Zumdahl92 93 149Outline 150Definition of Enthalpy 150Definition of Molar Heat Capacity C 150Calculating using C 150Changes in 149ProblemsZ911Z92325no c. Quick Review of Concepts. We have been introduced to heat producing (. exothermic. ) reactions and heat using (. endothermic. ) reactions. Heat is a measure of the transfer of . energy. from a system to the surroundings and from the surroundings to a system. 2. . Know and be able to account for the trends in reactivity with water. , the relative solubility of the hydroxides and sulfates. . The Trend . Hydroxides increase in solubility down the group.. Sulfates decrease in solubility down the group.. n, For a solution prepared using 1 kg of solvent, water and m ()()HaqwMHaqHaq111 kg m==
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The chemical potential of the solvent in an aqueous solution is related to the molality of solute j, m () n, For a solution prepared using 1 kg of solvent, water and m ()()HaqwMHaqHaq111 kg m==
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The chemical potential of the solvent in an aqueous solution is related to the molality of solute j, m () Internal Energy Equation. ΔE = Q + W = Q . + . PΔV. If the reaction is carried out at a constant volume (ΔV = 0) , then ΔE = Q. If volume is constant, any heat added or removed changes the internal energy. 12.1 Types of Enthalpy Change . 12.2 Born-Haber Cycles. 12.3 Enthalpy Changes – Enthalpy of Solution. 12.4 Mean Bond Enthalpy. 12.5 Entropy. 12.1 Enthalpy Change – Ionic Compounds. Learning Objectives:. Bonds and Energy. Breaking chemical bonds . requires. energy. Forming chemical bonds . releases. energy. The amount of energy required or released for a chemical process depends on the number and types of bonds that are formed and broken. 2016. School and Workshop . in Cryogenics . and Quantum Engineering. 26. th. September - 3. rd. October 2016. Aalto University, Espoo, Finland. Introduction to Dilution . Refrigerators. . Part I-. REACTIONS. Energy in Reactions. Some chemical reactions . release. heat to the surroundings. These are called . EXO. THERMIC. reactions. Heat . EXITS. the reaction. Some chemical reactions . absorb. Heat Capacity. Specific Heat Capacity (c): . the quantity of thermal energy required to raise the temperature of 1 g of a substance by 1°C.. Units are in J/g∙°C. Heat Capacity. Specific . heat capacity values can be looked up in tables. Spontaneous Reaction. A reaction that occurs without outside intervention.. Once it occurs it can be fast or slow.. It can go to completion. (Recall the three products produced :. Precipitate (table F), gas, or water.). Using the grid to solve for desired . quanties. . Recap . An . exothermic. change is a reaction that releases energy: energy can be thought of as a product . An . endothermic. change is one in which the energy must be added for the reaction to occur: energy can be thought of as a reactant . Enthalpy . is a state function . (the pathway does not matter) with . the symbol . H. ..  . H . = E . P V. E . is the internal energy of the system, P is the pressure of the system, and V is the volume of the system.. Enthalpy . is a state function . (the pathway does not matter) with . the symbol . H. ..  . H . = E + . P V. E . is the internal energy of the system, P is the pressure of the system, and V is the volume of the system..