Chemical/Physical Change and Temperature Flashcards
Van Hoff’s plot
plot of lnKº vs 1/T
What is the slope of a Van Hoff plot?
-∆rHº/R
What is the y intercept of a Van Hoff plot?
∆Sº/R
What does ∆rHº represent in a Van Hoff plot?
how rapidly Kº changes as a function of temperature
How do reactions shift with an increase in temperature?
they will shift toward the endothermic direction to counteract the change
How do reactions shift with a decrease in temperature?
they will shift toward the exothermic direction to counteract the change
How is a reaction with positive ∆rHº and positive ∆rSº favored? (endothermic with increase in entropy)
Product favored at high temps and reactant favored at low temps
How is a reaction with negative ∆rHº and negative ∆rSº favored? (exothermic with decrease in entropy)
Product favored at low temps and reactant favored at high temps
How is a reaction with positive ∆rHº and negative ∆rSº favored? (endothermic with decrease in entropy)
Reactant favored at all temps
How is a reaction with negative ∆rHº and positive ∆rSº favored? (endothermic with increase in entropy)
Product favored at all temps
