Equilibrium

This past unit has been very eventful. We have covered everything there is to know about equilibrium from Le Châtelier's Principle to its connection with Thermodynamics. Equilibrium is basically another term for reversible reactions. This means the reaction is constantly forming products from reactants as well as reactants from products. When we work out these equations, we usually separate them into sides, left for reactants, right for products. In actuality, there are no distinct sides in a reversible reaction because these reactions are intermingled with each other in a container. Equilibrium is reached when the forward and reverse reactions equal each other.

Calculating the equilibrium of a system is actually pretty simple. We use the equilibrium constant, Keq, to evaluate these reactions. In order to calculate Keq, follow the link here and look at slide 13. Basically, it is merely products/reactants. There are two main forms of Keq. They are Kc and Kp. Kc has to deal with with concentrations and is constant for concentration of moles. Kp however is constant for the pressure of the system. Temperature is the only factor that can affect K in any way.

Many of the main concepts of equilibrium can be seen in the picture below and all have to do we Le Châtelier's Principle. According to his principle, we can see that if you increase the moles of a reactant, the equilibrium shifts right and the other reactant's moles decrease. The same goes for products. This is very similar to the reverse process in that when the moles of a reactant decrease, the equilibrium shifts to the left side and the other reactant's moles increase. The same goes here for decreasing products.

There are also other factors that will either make equilibrium shift to the product side or reactant side. Adding heat to a reaction can alter the equilibrium as well depending on the type of reaction that is taking place. If the the reactions is endothermic and you add heat, the reactions will shift to the product side or right side. If the reaction is exothermic and you add heat, the equilibrium will shift to the reactant side or left side. This is very similar to adding moles in a reaction. An endothermic reaction needs heat to react and form product, so therefore heat is on the reactant side in that situation. An exothermic reaction creates heat in the product, so therefore heat is on the product side in that situation. Lastly increasing pressure of a reaction cause the reaction to shift to whichever side has less moles. This attempts to balance out the products and reactants. If you decrease pressure the reaction will shift to the side with more moles or the more condensed molecules. Moles of reactions are judged by their stoichemetric coefficients. 

Overall, this unit does not seem very difficult. My participation in class has been very good the past few weeks and I hope to see an improvement on my test scores because of that. I feel very good about the material overall and I feel I have a very good grasp on all of the concepts at hand. The equilibrium worksheets really have helped me to figuring out how to solve problems that do deal with equilibrium. The concept test questions are still pretty difficult but I feel like if I study and review them properly, I should have no problems on the next test!

1/13-1/20: Gases

This past week was a very eventful one. It feels very strange to be writing a blog after not having to write one for such a long period of time. Alas, this past week to week-and-a half, we covered a vast majority of the Gases unit and are just about ready to finish it. The main areas we covered were KMT, Partial Pressures and Mole Fractions, and Real Gases. We also covered Ideal Gases and how to calculate them as well.

Last week, we had just previously learned about Real Gases and several key formulas we needed to know about them. These formulas include Charles Law, Boyle's Law, Gay Lussac's Law, Avogadro's Law, the Combined Gas Law, and the Ideal Gas Law. We used these formulas to solve basic problems involving mass or the moles of an reactant/product, volume, pressure, and temperature. A list of these formulas can be found at the link below. This list also includes Dalton's Law of Partial Pressures and Van Der Waals's equation.

Gas Laws

After learning about gas laws and how to calculate these different problems, we dove into a new topic called KMT or Kinetic Molecular Theory. Here, we learned about the Main Tenets of KMT such as they have negligible volume as well as negligible attractive and repulsive forces. We also learned that smaller molecules have a larger root mean square speed than larger molecules. One of the bigger concepts we learned with KMT though was effusion, the escape of tiny gas particles through a small hole in space. We could also see larger molecules generally effused out of a substance much slower than smaller particles did. this can be seen in Graham's Law of Effusion shown below.

We finished out the week learning about Real Gases and what makes a gas stray from ideal behavior. We looked at how we could see this separation using the van der Waals equation. This equation had several parts (such as "a" and "b") that allowed us to further understand how theses gases may stray from ideal behavior. On Thursday, Dr. Finnan conducted an awesome demonstration using Liquid Nitrogen that was renowned by the entire class as one of the coolest things they've ever seen.

Overall, we learned a lot of new concepts and important information regarding Gases over the past few weeks. I still have a few unanswered questions regarding some of the key concepts but once I prepare for the Wednesday test by reviewing the PowerPoints and Hotpots, I'm sure the information will become much more clear. My participation in class these past few weeks has much improved from previous weeks but is still something I really need to work on moving forward. On a scale of 1-5, I would rate my understanding at a 4 of the information we've learned over the past few weeks. I need to study pretty hard this week in order to be prepared for the test. Once I review these formulas for Partial Pressures as well as the basic concepts, I should be able to master all of this material.