Chemistry 130 Chapter 5 Notes!
Chemistry 130 Chapter 5 Notes! CHEM 130 - 003
Popular in General Chemistry II
Popular in Chemistry
This 0 page Class Notes was uploaded by Izabella Nill Gomez on Thursday November 12, 2015. The Class Notes belongs to CHEM 130 - 003 at University of Tennessee - Knoxville taught by Bin Zhao in Summer 2015. Since its upload, it has received 37 views. For similar materials see General Chemistry II in Chemistry at University of Tennessee - Knoxville.
Reviews for Chemistry 130 Chapter 5 Notes!
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 11/12/15
Chemistry 130 Chapter 5 Notes Thermodynamics the study of energy and its transformations Thermochemistry relationships between chemical reactions and energy changes that involve heat Energy capacity to do work or transfer heat Work energy used to cause an object to move against a force Heat energy used to cause the temperature of an object to increase KE 1 2 Kinetic energy the energy of motion Tim V Potential energy an object has this relative to its position to other objects quotStoredquot energy that arises from the attractionsrepulsions one object experiences with another Electrostatic Potential Energy arises from interactions between charged particles proportional to the electric changes on the two interacting objects Q1 Q2 kQ1Q2 Eel d k is the constant of proportionality As d becomes in nitely large Eel goes to zero When Q1 Q2 have the same sign the particles repel each other and Eel is positive PE decreases as particles move farther apart and vice versa SI unit for energyJoule 1 cal4184J The energy that kinetic energy possesses results from the rising temperature in a reaction The potential energy is from chemical energy System portion of the universe used for study everything else is surroundings Open svstem is one where matter and energy is exchanged with surroundings Closed svstems do not do this An isolated svstem is one in which neither energy nor matter can be exchanged with its surroundings Force any push or pull exerted on an object WFd Heat is transferred from a hotter object to a colder one Energy as heat is transferred from the hotter system just reacting substances to cooler surroundings everything else First Law of Thermodynamics energy lost by the system is gained by surroundings and vice versa energy is conserved Internal Energy E sum of all the kinetic and potential energies of the components of the system Generally the numerical value is not known Concerned with the change in AEEfinalEinitial Positive AE energy gained by the system and lost to by the surroundings Negative AE energy lost by the system and gained by the surroundings System may exchange energy with the surroundings as heat or work Al 1439lquot 1heat WZWOFkgt When heat is added to a system or work is done on a system internal energy increases When work is done to the system w is positive The same with heat When heat is lost and work is done by the system internal energy is lowered Positive I Negative q heat gained heat lost w work done to the system work done by the system 3 net gain by system net loss by the system Endothermic process in which the system absorbs heat Heat ows into the system from the surroundings EX ice melting Exothermic process in which the system loses heat Heat ows out of the system to the surroundings EX combustion of gasoline State function property of a system that is determined by specifying the system s condition Value depends only on present state of the system not the path taken EX AEEPVAH Heat and work are not state functions Enthalpy Internal energy plus pressure times volume H E PV also state function Pressurevolume work work involved in expansion or compression of gases When pressure is constant Wz PAV A VzV nalViquoti ial pressure is always positive or zero Because the expanding system does work on the surroundings w is negative volume decreases AHAEPAV AHqpwwqp where pressure is constant so where qp is heat when pressure is constant The change in enthalpy equal the heat qp gained or lost at constant Pressure AHZ Ip When qgtO the reaction is endothermic When AH is positive heat is gained endothermic state function When AH is negative heat is lost exothermic state function AHZH products Hreactants Enthalpy of reaction enthalpy change that accompanies a reaction aka heat of reaction Aern 1 Enthalpy is an extensive property 2 AH for a reaction is equal in magnitude and opposite in sign for the AH of the reverse reaction 3 Enthalpy change for a reaction depends on the states of the reactants and products if gas less heat is readily available Heat capacity amount of heat required to raise the temperature of a substance by 1 K or 1 deg C Molar heat capacity heat capacity of one or mole of a substance Cm Speci c heat capacity heat capacity of one gram of a substance Cs quantity of heat transferred Grams of a sa bstaneegtllt Temperature Change When a substance absorbs heat the temperature increases qZCsmAT qsoln qrxn qsolrz Csmm g of S01 qrxn If A Tgt O V am lt0 the reaction is exothermic Combustion reactions are studied using a bomb calorimeter which withstands high pressures sample ignited with electricity and heat absorbed by water which measures the change in temperature qrxnCcalAT Cw is the speci c heat of calorimeter Carried out at constant value AE is measured Hess s Law states that if a reaction is carried out in a series of steps AH for the overall reaction equals the sum of the enthalpy changes f or the individual steps Overall enthalpy change is independent of the number of steps and the path by which the reaction is carried out consequence of being a state function AH For a particular set of reactant and products is the same whether the reaction takes place in one step or a series of steps Standard enthalpy change enthalpy change when all reactants and produces are in 0 their standard states AH 6 0 Standard enthalpy of formation AHf change of enthalpy for the reaction that forms one mole of compound from its elements with all substances in standard states 0 If elements standard statescompound 1 mol in standard then AHAHf Standard enthalpy of formation of the most stable form of any element is zero because no formation reaction is need when the element is already in its standard state
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'