CHM 101 1st Edition Lecture 11Lecture Overview I. Identifying ElectrolytesII. Concentrations of solutionsIII. MolarityIV. DilutionsV. pH and pOH scaleLecture 10I. ThermochemistryII. Potential and Kinetic Energy III. Units of Energy IV. System and Surroundings V. Heat Thermochemistry • Thermodynamics – the study of energy and its transformations• Thermochemistry – the study of energy changes accompanying chemical reactionsThe nature of energy • Energy – the capacity to do work or transfer heat • Energy can’t take more than one formo Work – energy used to cause an object to move o Heat – energy used to cause the temperature of an object to increaseKinetic Energy – the energy of an object due to its motion• Ek = ½ mv2o M – masso V – velocity • 2 types of kinetic energyo Mechanical energy – from the motion of macroscale objects These 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.o Thermal energy – from the motion of nanoscale objects (atoms and molecules)Potential Energy – energy an object has due to its position relative to other objects • Gravitational energy – due to an objects height• Electronic energy – is attractive energy between 2 charged particles • Chemical potential energy – stored within molecules o Breaking bonds consumes energyo Forming bonds releases energyUnits of Energy • 1 joule = 1 kg x m2/s2• Calorie – amount of energy required to raise the temperature of 1 gram of H2O from 14.5 degrees Celsius to 15.5 degrees CelsiusSystem and Surroundings • Energy is transferred between different regions of the universe • When studying these transformations it is important to define the system (the part we are interested in) and the surroundings (everything else)• Closed system – can exchange energy but not mass with in its surroundings • Energy can be transferred as heat or work (or both)• Energy can be transferred to te surroundings from the system or to the system from the surroundings First Law of Thermodynamics• Energy cannot be created nor destroyed, only converted from one form to anothero Energy is conservedInternal Energy of a System – sum of all the kinetic and potential energy of all atoms, molecules, or ions in a systemChange of Internal Energy of a System∆E = Efinal – Einitialo Energy going out of a system ∆E is negativeo Energy going into a system ∆E is positive Heat – changes in the internal energy of a system occur in the form of both heat being lost or gained by the system and work being done on or by the system∆E = q + w• Q is heat and w represents work• Heat absorbed from surroundings by the system q is positive • Heat released from the system to the surroundings q is negativeWork• Work is done on the system by its surroundings w is positive • Work is done by the system on its surroundings w is