# Understanding how the equilibrium constant (Keq) relates to enthalpy change. Introductory thermodynamics. Attachment in Word.

Which reaction is more exothermic?

A reaction with Keq=500 or a reaction with Keq=0.002?

#### Solution Preview

...be sure you've memorized these equations and fully understand how to use them! Some professors will also ask you to memorize the value of R (the gas constant) -- check with your professor!.

DG = -RTln(Keq)

(***Here, "D" means delta.)

From the above equation, a large value of Keq will yield a large positive value for DG. (For example, ln(500) = 6.2, whereas ln(0.002) = -6.2.)

That ...