BCHS 3304 Lecture Notes - Lecture 2: Joule, Thermodynamics, Equilibrium Constant

• School: University of Houston
• Department: Biochemistry
• Course: BCHS 3304
• Professor: Yeo Hye- Jeong

Document Summary

Units: length= use angstrom when describing bond lengths between elements. 1 angstrom= 1e-10 meters can be determined through x ray crystallography or electron microscopes: time= measured in seconds. For enzyme reactions, use milliseconds: energy= measured in joules, or kcal. Q represents heat: heat= transfer of energy, is (-) if the system gives off heat, is (+) if the system absorbs heat. Must thus be measured through indirect means. S= h/ t: h is enthalpy. Enthalpy= total energy of a thermodynamic system: t is temperature. When g is (-) reaction is spontaneous. When g is (+) reaction is nonspontaneous. When g is 0 the reaction is at equilibrium: no net movement to the right or left. Keq = equilibrium constant= [c]c eq [d]d eq / [a]a eq. If for example the reaction is: aa cc + dd. The equilibrium constant uses the concentrations of the products and reactants at equilibrium.