This may have been the largest Chem Talk reading we have ever done in this class. Section 4.8 covered all sorts of things including spontaneity, enthalpy changes, entropy changes, spontaneity in nature, polymers, and how temperature affects rubber bands. The book talks of systems and surroundings and how they deal with how a certain scientist wants to investigate. In order to see and consider change, a scientist must first understand what the system is doing and how the surroundings effect what happens. Open systems are systems that allow energy to pass through them, and closed ones contain energy within. An interesting concept is the law of conservation of energy, which states that energy is never destroyed or created, but transferred. The rest of this little section was a little overview of positive and negative changes in entropy and enthalpy which is a little bit of a challenge to grasp, but is accomplishable. There are certain combinations in nature that allow for spontaneous reactions, depending on whether both the entropy and enthalpy are negative or positive. The Gibbs free energy equation can usefully tell if a reaction would occur spontaneously or not, which is cool. If left with a positive answer after using the equation, the reaction is not spontaneous and vise versa. The talk ended with a discussion about the entropy and enthalpy of rubber bands when they are both stretched and contracted, which seemed pretty interesting, but we were not able to test this in class, which is unfortunate. All in all, this talk gave me a better picture around entropy and enthalpy.