# MCAT Gen Chem 2

 Thermodynamic Whether or not a process or reaction can occur. Kinetic How fast or slow a process or rection can occur. Exothermic energy coordinate diagram Endothermic energy coordinate diagram Convection Fluid movement caused by the hotter portions of a fluid rising and the cooler portions of a fluid sinking. Radiation Electromagnetic waves emitted from a hot body into the surrounding environment.Light colors radiate and absorb lessDark colors radiate and absorb moreBlack Body Radiator - perfect theoretical radiator Conduction Molecular collisions along a conduitAnalogous to current flow through a wire or H2O through a pipe Heat Capacity (definition) The amount of energy (in Joules or Calories) a system can absorb per temperature unit (J/K or cal/˚C). Heat Capacity (formula) C = q/∆T Specific Heat Capacity (definition) Is for a given substance only and is defined as the heat capacity per unit mass. Specific Heat Capacity (formula) q = mc∆T Specific Heat of Water 1.0 cal/g˚Cor4.18 J/g˚C First Law of Thermodynamics ∆E = q + wWork done on the system (+)Work done by the system (–) Second Law of Thermodynamics Heat cannot be changed completely into work in a cyclical processEntropy in an isolated system can never decrease Third Law of Thermodynamics Pure substances at absolute zero have an entropy of zero Zeroth Law of Thermodynamics Temperature exists Celsius – Kelvin conversion 0˚ C = 273.15 K-273.15˚ C = 0 KAbsolute zero = 0 K Kinetic Energy of Gasses (formula) KE = 3/2kTk = Boltzman's constant (1.3806503 e –23 m2 kg s-2 K-1) Enthalpy (∆H)The energy contained within chemical bonds or HEAT Entropy (∆S)A measure of the randomness or disorder in a system Standard State Standard State is 25˚ C (298K) and ∆H = 0*For thermodynamics problems STP STP (standard temperature and pressure) is 0˚ Celsius (273K) and 1 atm*For gas problems + ∆S = Increased randomness, energy released and available to do work – ∆S = Decreased randomness, energy is required to "create" increased order and that energy is thus unavailable to do work Entropy (∆S) increases with: (5 things) 1. Increased number of items/particles/etc. (Gas trumps # of moles or particles. This means that if two moles of reactants makes one mole of product and that product is a gas, it is still +∆S)2. Increased volume3. Increased temperature4. Increased disorder5. Decreased pressure (the higher the pressure the more packing and order of molecules) Gibbs Free Energy (∆G) ∆G = the amount of "free" or "useful" energy available to do work. -∆G = Spontaneous; exothermic+∆G = Non-spontaneous; endothermic Rate Order Graphs 0 order: [A] vs. time is linear with slope -k1st order: ln[A] vs. time is linear with slope -k2nd order: 1/[A] vs. time is linear with slope k3rd order: 1/2[A]2 vs. time is linear with slope k Fundamental Thermodynamic Relation formula ∆G = ∆H - T∆S ∆G - Gibbs∆H - Enthalpy∆S - EntropyT - Temp K Entropy signs (+) means more disorder or increased entropy.(–) means more order or decreased entropy. AuthorMaki6tu ID129150 Card SetMCAT Gen Chem 2 DescriptionChem 2 Updated2012-08-02T19:29:40Z Show Answers