University:
York University
Course:
CHEM 1001 | Chemical Dynamics
Academic year:

2022
Views:

212

Pages:

2
Author:

Niklas

01/12/2022 Chapter 9 01/14/2022 "What we want to know about reactions -is it energetically foxsible? -is it spontaneous? •Spontaneous will the reaction go if you had all the hine in the world - how much energy ergy is released? - can we got anything useful from that energy? Exothermic reactions: a system <0 -products have lower energy than the reactants -in a non-spontaneous reaction, energy needs to be added -bonds formed energy released Net onergy difference behwan bonds broken and bonds formed Potential energy energy of bonding -covalent of non-covalent -monotomic ideal gas has no potential energy •Kinetic Energy energy of atomic motion (of T) or energy associated with temperature -KE= 3/2 ART First Law of Thermodynamics→ energy is conserved "System + surroundings = universe -system: thing we are interested in - surroundings = everything else AE:+ of system -AE of surroundings ΔΕ heat added to work done on syskm ΔΕ = 9+ -920: system gains heat from surroundings ->0: work done on the system by surroundings -9ot w are path-dependent functions that add to a state function State function something that does not depend on anything else - AE temperature ۹:۵۴ -not dependent on the pathway - represented with capital letters -any sum or difference of State functions is also a state function Chapter 9 01/14/2022 01/19/2022 • Examples of paths -constant Por T - constant volume (w=0) - adiabatic (4-0) When work is done on surroundings, the sign of w is negative expansion of a gos against a constant external pressure ish++; ۵۷۰ N= -PAV P ArA (b) Final expansion of an ideal gas into a vacuum -w=0 because external pressure is zero -9-0 because nothing about the kinetic energy changes - AE-O because 9+w=0 Reactions at constant pressure - enthalpy - H -H-E-PV OH=AE+PAV at constant pressure -AH-9, (9 is state function at constant pressure) -AE=qu (q is stale function at constant volume) - ΔΕΔΚΕΔΡΕ > not the same Two causes of AV #0 in AH-DE-PAU -Chemical or physical change in which Angas #0 -hent or cool a gas, ATED