As always… Lon-Capa assignments Lecture videos Textbook Read Do text homework Video for Wednesday (10/18): Reversible Processes

Questions To Consider How can we predict which reactions are spontaneous (and what do we mean by spontaneous)? How can we provide support (mathematical and qualitative) for observations? Ice cream melts Coffee cools Why do systems reach equilibrium? That is, why doesn’t the ball go all the way down the hill?

Clicker Question Is the “pop bottle reaction” spontaneous or not spontaneous? a) Spontaneous b) Not spontaneous

How to Think About Entropy Entropy is related to heat/temperature. ΔS = qrev/T Entropy as “disorder”. S = k●logW

Temperature: measure of KEavg

From the videos and text… …show how probability plays into all of this. …show that thermal equilibrium is preferred when two bodies of different temperatures are put in contact with one another. …see why entropy is related to the logarithm of the number of configurations or microstates. …discuss what “reversible” means when we say the change is entropy equals qrev/T?

Clicker Question How many different configurations are there for the most probable distribution when the stopcock is opened? a) 1 d) 20 b) 6 e) 64 c) 15