12/9-12/13

            This tri in AP Chemistry we have been covering the topic of Thermodynamics. This topic covers both enthalpy and entropy. We spent lots of time in class doing worksheets and using our famous white boarding technique. This technique has been very beneficial for myself and many other classmates all year. We also spent a little bit of time doing a quick mini-lab that involved precipitates and net ionic reactions.

            In our introduction to Thermdynamics we discussed the difference between heat and temperature. From our discussion we concluded that heat is a measurement of the total energy that is present in the system while temperature is the measurement of the heat content of the system. In our introductory discussion, we also figured out that heat is due to the breaking or making of bonds. Temperature is also related to the transfer of heat. Lastly we learned that when heat leaves the system and goes to the surroundings it is considered an exothermic process and when heat goes into the system from the surroundings it is considered an endothermic process.

            Next we moved onto calorimetry. Here we continued to work on distinguishing between endothermic and exothermic processes. We worked on some worksheets using the formulas that we learned for the change in heat. Change in heat is equal to the mass multiplied by the specific heat capacity and the change in temperature. Calorimetry is useful to us because from this method we can find the energy change in the system by finding the energy change in the surroundings. We also talked about the enthalpy of fusion and the enthalpy of vaporization. Enthalpy of fusion has to do with the process of melting and the breaking of bonds. When vaporization occurs the rest of the bonds are broken.

            In our last topic we discussed entropy. Entropy can be defined as the possible number of microstates that are available to the system. It is represented as delta S. Entropy is greater than zero when melting or vaporizing takes place. It also occurs when the number of moles increases. Entropy can be calculated as the sum of the products minus the sum of the reactants. The last thing that involved entropy was Gibbs free energy law. This was used to figure out whether or not a process is thermodynamically favored.

            These were all of the main ideas that we covered this week. Basically they all go hand in hand with each other as they all fall under the umbrella of thermodynamics. Most of this unit had to do with math and I found that very beneficial to my personal understanding of the unit. Equations and numbers make some of the concepts easier to understand. With the equations visible to me and understanding each of the factors in the equation, I can fully realize what is going on in the process of the reaction. I would say that my participation was there this week as I asked a lot of questions pertaining to some of the problems in our worksheets. Overall, I would put my understanding with this material at about an 8/10.

Here is a video previewing a step of our lab next week.