PROBLEM: The equilibrium constant for the butane < - - > isobutane isomerization reaction is 2.5 at 25°C. If 1.75 mol of butane and 1.25 mol of isobutane are mixed, is the system at equilibrium? If not, when it proceeds to equilibrium which reagent increases in concentration? Calculate the concentration of the two compounds when then the syste, reaches equilibrium. Assume volume is 1.00 L Q is less than K, so the system shifts to form more isobutane. Set up an ICE chart butane - - > isobutane Initial(M) 1.75 1.25 Change(M) –x +x Equilibrium(M) 1.75 – x 1.25 + x Solve for x x = 0.89 [butane] = 1.75 – x = 0.86 M [isobutane] = 1.25 + x = 2.14 M