CHEM 101 1nd Edition Lecture 19Outline of Last Lecture I. SpectroscopyOutline of Current Lecture I. Energy and ChemistryII. Temperature and HeatIII. System and SurroundingsIV. Specific Heat CapacityV. Change of StateCurrent LectureI. Energy and Chemistrya. What is energy?i. The capacity to do workii. Yu do work walking to class in the morningiii. Food is the source of chemical energy that allows you to do this workb. Energy can be classified as kinetic or potentiali. Kinetic energy is energy associated with motion1. Motion of atoms, molecules, or ions at the subatomic levela. Thermal energy2. Motion of macroscopic objects like a thrown footballa. Mechanical energy3. Movement of electrons through a conductora. Electrical energy4. Compression or expansion of the spaces between molecules in the transmission of sounda. Acoustic energyii. Potential energy results from an object's position and includes:1. Energy posed by a ball held above the floor ad by water t the top of a waterfalla. Gravitational energy2. Energy stored in fuelsa. Chemical energyb. All chemical reactions involve change in chemical energyThese 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.3. Energy associated with the separation of two electrical chargesa. Electrostatic energyiii. Potential energy and Kinetic energy can be interconnected1. As water falls over a waterfall, its potential energy is converted to kinetic energy 2. The kinetic energy of falling water can turn a turbine to produce electricity which can be stored as chemical energyc. Conservation of Energyi. Law of Conservation of Energy1. Energy can neither be created or destroyed2. Energy can be converted from one from to another3. The total energy of the universe is constantII. Temperature and Heata. Heat is not the same s temperaturei. The more thermal energy a substance has the greater the motion of its atoms and moleculesii. The total thermal energy in an object is the sum of all the individual energies of all the atoms, moles, and ions in the objectiii. Heat transfer always occurs from an object at higher temperate to an object of lower temperatureb. How does a thermometer work?i. When a thermometer is placed into a beaker of hot water, the atoms of mercers in the thermometer try to reach thermal equilibrium with water (heat is transferred)ii. The heat transfer increased the kinetic energy of the Hg atomsiii. The Hg atoms move more rapidly and the space between the atoms increases slightlyiv. The increase in Hg(l) volume causes the column of Hg to risev. This continues until the thermal energy of the Hg is the same as that of the water (no additional heat is transferred)III. System and Surroundingsa. In thermodynamics we define the terms system and surroundingi. System: an object, or collection of object, being studiedii. Surroundings: include everything outside the system that can exchange energy and/or matter with the systemb. Exothermic vs. Endothermici. Exothermic:1. System generates heats but then transfers that to the surroundings a. Negative2. The system loses heat to the surroundingsa. The energy of the system decreasesii. Endothermic:1. System pulls heat from the surroundingsa. Positive2. The system gains heat from the surroundingsa. The energy of the system increasesiii. Directionality of Heat Transfer1. Exothermic: Heat transfers from system to surroundingsa. Chemical reaction heats airb. Heat always trans from the hotter object to the cooler object2. Endothermic: Heat transfers from the surroundings to the systema. Bunsen burner heats ice.b. Heat always transfers from the hotter object to the colder objectIV. Specific Heat Capacitya. When an object is heater or cooled, the quantity of energy transferred depends oni. The quantity of materialii. The magnitude of the temperature changeiii. The identity of the material gaining or losing energyiv. If a phase change has occurredb. Specific Heat Capacity (C)i. The energy transferred as heat that is required to raise the temperature of 1 gram of a substance by 1 kelvin1. Table of Constants in Textbook, Appendix D Table 11ii. Units are J/ gK (joules per gram per Kelvin)iii. Energy gained or lost as heat when a given mass of substance is warmed or cooled can be calculated with 1. q = C x m x ΔT2. q = m x C x ΔT a. Can remember with mCATiv. q is energy gained or lost1. + (gain)2. - (loss)v. m is the mass of the given substancevi. C is the Specific heat capacityvii. ΔT is the temperature change1. Tfinal - Tinitialc. Examplesi. Calculate the energy that must be transferred as heat to a 10.0 g sample of copper to raise its temperature from 298 K to 598 K1. q = C x m x ΔT2. Specific heat for Cu(s) is 0.385 J/gK3. q = (0.385 J/gK)(10.0g)(598K-298K) = +1160 Ja. Note that the value of q is positive -- meaning that the thermal energy of the copper has increased by 1160 Jii. In an experiment, it was determined that 59.8 K was required to raise the temperature of 25.0 g of ethylene glycol by 1.00 K. Calculate the specific heat capacity of ethylene glycol from these data.1. q = C x m x (delta)ΔT2. 59.8 J = C(25.0 g)(1 K)3. C = 59.8 J / 25.0g 1K = 2.39 J/ gK4. Molar Heat Capacity: similar to specific heat capacity but based on1 mol rather than 1 g quantitiesiii. If 25.0 g of Al cool from 310 degrees C to 37 degrees C, how many joules of heat energy are lost by the Al?1. Specific heat of Al(s) is 0.897 J/gK2. q = (0.897 J/gK)(25.0g)((37+273)K - (310 +273)K)3. q = (0.897 J/gK)(25.0g)(-273K) = -6120 Ja. Note the negative sign on q signals heat “lost by” or transferred out of AlV. Change of Statea. A change of statei. Converting between the different states of matterb. When a solid melts, its atoms, molecule, or ions move about vigorously enough to break free of the attractive forces holding them in ridged places in the solid latticec. No bonds (covalent) are brokeni. H2O(l) --> H2(g) + O2(g) NONONONOd. When a liquid boils, particle move much farther apart from one another, to distances at which attractive forces are minimal.e. Energy is required for both processesf. Heat of Fusioni. Energy transferred as heat that is required to convert a substance from a solid at its melting point to a liquidg. Heat of Vaporizationi. Energy transferred as heat to convert a liquid at its boiling point into vaporh. Temperature is constant throughout a change of