Chm 471 Biophysical Chemistry I Exam 1 Review

CHM 471 BIOPHYSICAL CHEMISTRY I EXAM 1 REVIEW Gibbs Free Energy - ANS-ΔG = ΔH-TΔS ΔG = -TΔS_total ΔG is a measure of the maximal, non-expansion work a system can perform. Entropy change (ΔS) - ANS-ΔS = q_rev/T Entropy change for physical or chemical transformation approaches 0 as T - 0. Entropy of all perfectly crystalline substances are the same at T = 0 K, and are equal to 0. Carnot Cycle efficiency - ANS-Ɛ = -w_cycle/q = (Th-Tc)/Th Maximum efficiency is 1. 0th Law of Thermodynamics - ANS-If system A and B are in thermal equilibrium with system C, then A and B are in thermal equilibrium with one another. 2nd Law of Thermodynamics - ANS-The entropy of an isolated system tends to increase. 1st Law of Thermodynamics - ANS-Internal energy of an isolated system remains constant. Carnot Cycle work equation (1 cycle) - ANS-w_cycle = -nR(Th-Tc)ln(Vb/Va) Represents maximum amount of work you can extract from one cycle. Change in internal energy - ANS-ΔU = q + w (work done on sys) = q - w (work done by sys) Thermal motion proof - ANS-Equation for force of particles on wall of a container. Sub in equation for acceleration of particle. P = F/A = F (1/l^2). Vx = Vy = Vz for a gas. E_k = 0.5mv^2. P = nRT/V and n = N/N_A. K_B = R/N_A. Heat capacity - ANS-C = q/ΔT Fourth Law of Thermodynamics - ANS-Defines temperature. Thermal motion - ANS-E_k = (3/2)(K_B)(T) Work (reversible) - ANS-w = -nRT ln(Vf/Vi) Work (irreversible) - ANS-w = -P_ext ΔV Ratio of populations - ANS-Individual particle: N_2/N_1 = e^(-ΔE/(K_B*T)) Molar: N_2/N_1 = e^(-ΔE/RT) Change in internal energy (constant volume) (aka heat, since ΔU = q at constant volume) - ANS-q = n(C_m)(ΔT) Heat capacity (constant volume, molar) (C_v,m) - ANS-C_v,m = ΔU/nΔT Heat capacity (constant pressure, molar) (C_p,m) - ANS-C_p,m = ΔU/nΔT + R (C_p,m = C_v,m + R) Enthalpy - ANS-H = U + PV Constant volume enthalpy - ANS-ΔH = q Heat capacity (constant pressure) defined in terms of enthalpy - ANS-C_p = ΔH/ΔT Calorimeter equation - ANS-q_cal = IVt I = current (in A) V = voltage (in V) t = time (in sec) Differential scanning calorimetry (DSC) - ANS-Technique used to examine the decomposition of molecular complexes such as enzyme-substrate or receptor-ligand complexes at different temperatures.