This previous week was not very eventful in AP Chemistry. We spent the first half of the week reviewing for our big exam on stoichiometry which covered limiting reactants, empirical formulas, and percent yield. To reflect on our review in class, I thought it was extremely helpful in preparing me for the test. The moodle quizzes online really helped me learn material which I had not quite understood before, as well as help me get more practice with harder problems like the ones we would see on the exam. Redoing these quizzes several times allowed me to see more and more problems, which ended up being extremely helpful, as the problems on the moodle quizzes were very similar to the ones on the stoichiometry exam. To reflect on the actual exam itself, I thought it was a very good challenge, and although I did fairly well, I feel like I could have done much better if I had more time to study. There weren't any problems that I had never seen before in one way or another, and I was pretty confident about how I did. The only thing I need much more work on is learning how to use significant figures better. This definitely caused me to lose some points on the free response exam, which I cannot have happen, because this doesn't reflect my knowledge on stoichiometry, but rather on how to round numbers.
          After taking the test we began working with Lewis structures. To reflect on this topic, I thought the lewis structure pogil was comprehensible and fairly simple, although there was some stuff I did not quite understand. The main ideas we covered regarding lewis structures were how to figure out which atom is the central atom and how to form the covalent bonds. To determine which atom is the central atom, you must figure our the electronegativities of the atoms. Then, you find out which atom has the lowest electronegativity and place it in the center. Then you form covalent bonds with unpaired electrons from the outside atoms to the inside atoms. Although we didn't really go over these in class, resonance and bond order were discussed in the lectures. I found these to be quite confusing and I hope we work on them more in class because I didn't really understand these concepts. Overall I found the lectures online this week to be kind of challenging, and I hope we work more with them in class.

          
          Overall, this week was not very eventful so there is not much to discuss.  I found the activities that we did to begin gaining knowledge on Lewis structures pretty straightforward and the lectures on resonance and bonding orders a bit harder and more complicated. I realized from taking the test this week that I need to work harder on doing more practice problems especially involving  and studying harder to get a higher grade on the test. I would still rate my understanding on the past material covered on the test and the new material that we learned this week at about a 4 out of 5. I was able to participate fully in all of the activities we did this week and that helped me broaden my thinking about Lewis structures and how they really work.
http://www.youtube.com/watch?v=8JsK6rPpi70  - This is a good video that further helped me learn to draw lewis structures.

          This week we expanded greatly on stoichiometry. We moved on from basic stoichiometry problems into problems involving limiting reactants and yield. We also learned about empirical formulas and molecular formulas. As we deepen our knowledge regarding stoichiometry, the more the the concept build on each other. For example, the concepts we used to do basic stoichiometry problems at the beginning of the year have been crucial in helping us solve problems involving more complicated ideas such as yield, limiting reactanta, and empirical as well as molecular formulas.
          We dove into limiting reactants through a Pogil which we completed in class. I found this pogil to be very helpful because it explained limiting reactants in chemistry through examples that are unrelated to chemistry which helped me get a grasp on the topic. From there, we did worksheets which gave us practice solving problems involving limiting reactants. To find the limiting reactant you must find out which of the reactants produces the lesser amount of the product. To figure this out we used our knowledge and experience with mole ratios and molar mass to perform calculations. I found these problems to be very simple and straightforward.
          Next we moved on to more complicated but still fairly simple stoichiometry problems which required us to find percent yield. We used lectures and worksheets to help us understand the concepts involved in finding the percent yield. To solve yield problems you must: balance the equation, determine the limiting reactant, determine theoretical yield, divide actual yield by theoretical yield, multiply by 100%. The process of solving thee problems is fairly simple, largely because it does not involve any complicated calculations.
          The last thing we worked on this week was determining empirical formulas. Similarly to limiting reactants, we learned about empirical formulas through a pogil. At first the concept of empirical formulas was very challenging to me but once we did the pogil and worksheets it became more clear. An empirical formula is a formula which represents the simplest ratio among the elements of a compound, however formulas with the same base formula do exist. The next concept we tackled was finding molecular formulas by dividing the molar mass by the empirical molar mass. I found this concept pretty easy and simple to understand. We also worked a tiny bit on particle diagrams which I found to be extremely confusing, and this is something I definitely need more work on, I hope we tackle these a bit more in class next week before the test.

Overall, I thought this week I was able to understand most of the concepts we covered very well. Like I said, the thing I am having some problems with at this point are particle diagrams, these are very confusing for me and I need some more work on them. On a scale of 1-5, I would say I am a bout a 4 on my level of comprehension of the ideas in AP Chemistry this week.

          This previous week our class did a lab lab which examined the relationship between the molar concentration of a solution and absorbency. Furthermore we also studied molarity and worked with a couple of stoichiometry problems. These were the main areas we covered in class and on the Moodle this week and they are interconnected. We learned that concentration is directly related to molarity and we used this information to aid us in our lab.
          The first activity we worked on this week was a lecture quiz online regarding molarity. The major and most important thing we learned from this quiz is the equation, Molarity (M) = moles of solute / volume of the solution in liters. This concept is critical to understand and is closely related to the idea of dilution we studied in the lab. Another important concept we learned from the lecture quiz is the fact that volume is temperature dependent. The first concept is related to the lab because in the lab we saw that the moles of solute (the blue dye) would decrease as we increased the amount of water in the solution and as the solution became more diluted. The temperature concept in the moodle   quiz is also related because it has to do with molarity and when the temperature goes up the volume goes up and the molarity will then decrease. Another thing we learned is about the different types of pipettes, their uses, and how they affect the amount of moles of a solution and the volume of a solution depending on which pipette you're using.

<-- We used a pipette like this in our lab to help accurately create the solutions.

<-- We used a cuvette to put the solution in and we put the cuvette in the colorimeter








          After doing the lecture quiz, we worked on  some difficult stoich problems. To do these we used the knowledge we previously had on molar mass, moles, and the relationship between grams and moles. Knowing this we were able to solve a lot of problems involving these concepts. An important equation for this secion was mass x molar mass = weight. by using this equation we were able to examine the relationship between moles, mass, weight, and atoms in the problems we did. Because the stoich problems were challenging for me, I looked for some extra help online and found the URL to a good video further explaining stoichiometry. http://www.youtube.com/watch?v=lVT0S-W_wEM
          The last thing we did this week was a lab examining the relationship between concentration and absorbency. To do this lab we first altered the concentration of many different solutions of blue #1 dye and water and finding the absorbency of the different solutions. Then we looked at different absorbency levels of Powerade and Gatorade G2 to find the concentration of blue #1 dye in these solutions. We then developed a linear equation between between these two variables and performed calculations with this knowledge. This lab required previous information from the lecture quiz and stoich problems.
          We came to figure out and understand these problems through experimentation and completing many problems in class. The thing that confused me the most this week was Beers law, especially since there was a problem we did in class on Friday that required us to apply Beers law. I would definitely like to gain a better understanding of the relationship.I participated very well this week, especially in the lab which I found to be very fun and interesting. Overall, on a scale of 1-5 I understand the material covered this week at about a 3. At this point I do not have any new questions to ask, but I need to review more so I can better understand everything.