Please sit in the indicated areas according to your recitation TA TA Ben TA Kriti TA Conner TA Pengchong 1 Clicker question Which of the following samples contains the largest number of atoms because there are 4 atoms in one mol of CH4 6 02214 x 10 23 x 4 A 1 0 mole of methane CH4 B Avogadro s number of CO2 molecules C 28 g of N2 D 18 g of water H2O E 1 5 x 1024 atoms of argon Ar 2 Clicker question After attending recitation yesterday I I feel more confident about locating information that I need for the course II I understand how the eBook is laid out III I still feel overwhelmed and I m not sure where to find things A I B II C I and II D III 3 Before next class Mon 8 31 Do the Week 1 Lectures 1 3 problems linked to the syllabus Read Lessons 02 1 02 2 and 02 3 including the reading guides and stop signs example problems Finish up ALEKS due Sun Sept 6 LA Office Hours Sunday 1 2PM in 109 Osmond Henry Aditi and Jacklyn Sunday 5 6PM in 109 Osmond Elli and Craig eBook 4 ALEKS How far have you gotten with ALEKS A ALEKS Who is ALEKS Some cool dude I should meet B I registered and then forgot about it C I finished the initial assessment only D I finished the assessment and started working in learning mode E I already finished all of ALEKS cause I m on top of my shtuff 5 FYI Do not fill out a sheet going around asking for your name and phone number I will never ask for such information from you See the Help Available section of the eBook to learn about all the free help available from the Chemistry department 6 Lesson 01 4 Introduction to energy 7 There are two forms of energy kinetic and potential energy Kinetic Energy energy of motion Mechanical Electrical Light moving mass 1 2 mv2 moving charge moving photons Sound Heat molecules moving uniformly molecules moving randomly Potential Energy stored energy Mechanical Electrostatic Chemical Nuclear Units of energy mass in a place where a force can act due to the interaction of charged particles bonds binding energy Joules J kg m 2 s 2 1 cal 4184 J First Law of Thermodynamics The law of conservation of energy The total quantity of energy in the universe is assumed to be constant Energy can neither be created nor destroyed Energy can only be converted from one form to anothers All energy lost by a system under observation must be gained by the surroundings and vice versa energy gained by the system is lost by the surroundings the specific part of the universe under study The system is and encompass the rest of the universe the surroundings internal Energy of the system is called energy Energy of system increases F01 4 1 Energy of system decreases 9 Internal energy Internal energy is the total energy E associated with a system the sum of all kinetic potential sources of and energy Internal energy is the capacity to do work and transfer heat You cannot define absolute energy only the change in energy E Esys Efinal Einitial To calculate E quantitatively delta E q w Know the signs of q and w all are considered with respect to the system Heat transferred out of system Work done by the system q 0 w 0 Heat transferred into the system Work done on the system q 0 w 0 10 State functions A state function is a function whose value does NOT depend on the pathway used to get to the present state Changes in state functions are path independent and only depend on the current state composition temperature and pressure State functions are written as uppercase letters E H P V T S q and w are not state functions but E q w is a state function Distance is not a state function but elevation is a state function Chemical Reaction E 11 Internal energy is a state function The internal energy of the 25 C beaker of water is the same regardless of whether it was prepared by cooling boiling water or melting ice F01 4 4 12 Clicker question What is the change in internal energy for the following system q 75 1 J w 25 3 J A 100 4 J B 49 8 J C 49 8 J D 100 4 J E 150 2 J 13 Electrostatic energy Coulomb Electrostatic energy is a form of potential energy that results from the interaction of charged particles repel attract Like charges one another and opposite charges one another repulsion attraction F01 4 2 more stable The more negative the electrostatic energy is the the system and more favorable the the interaction less stable The more positive the electrostatic energy is the the system and less favorable the the interaction 14 Electrostatic energy Electrostatic energy is defined by Coulomb s law E el Q1 Q2 d Interaction of two positively charged particles d 1 1 1 1 d 0 repulsion Interaction of two negatively charged particles d 1 1 1 d 0 repulsion 1 Interaction of two oppositely charged particles 1 1 0 attraction d 1 1 15 Clicker question Rank these in order of increasing electrostatic potential energy 0 5 d 0 5 d 1 1 I 4d 2 1 II 0 5 d 2 2 III A I II IV III B II I III IV C IV III II I D IV III I II E II III I IV Follow up Which has the strongest interaction 1 3 IV Lesson 01 5 Enthalpy 17 E at constant P is different from the E at constant V https chem110 science psu edu 01 5 enthalpy Dry ice CO2 is heated at constant V Dry ice CO2 is heated at constant P V 0 0 w V P V w P V q q q q Esys q w Esys qp P V Esys q w No work done Esys qp w H P V Esys qv 18 Enthalpy is defined as heat transferred at constant P H qp Quantitative definition E qp wp qp P V when P is constant qp E P V defines H Enthalpy qp Qualitative definition H is the heat exchanged with the surroundings at constant P For many chemical processes P V is small because V is very small and P is usually 1 atm H is a state function H is path independent Only need to know the initial and final state 19 Enthalpy H exothermic When Hrxn is rxn is releases rxn heat to the surroundings How do you detect this experimentally Temperature of surroundings increases endothermic When Hrxn is rxn is absorbes rxn heat from the surroundings How do you detect this experimentally Temperature of surroundings decreases 20 Lesson 01 6 Light energy 21 Light and other electromagnetic radiation behaves as a wave Wavelength peak to peak distance Frequency cycles waves per unit time m nm v Hz s 1 How are …