[header] How to study states of equilibria in organic reactions [title] Understand what happens when equilibrium occurs. [step] Chemical reactions that reach a state of thermodynamic equilibrium are typical of uncatalyzed reactions in which their energy profile shows net enthalpy change of the reaction that is close to zero. This means that the reaction neither releases heat nor absorbs heat. 
This type of reaction is not driven by thermodynamic force so that it reaches a state of equilibrium. Normally other thermodynamic functions are affected by this state of equilibrium.