Week of 9/9-9/13

            This past week we performed a lab looking at the relationship between concentration and absorbency. We also took a look at molarity and worked with a few stoich problems. These were the main ideas that we covered this week and they are very much related to each other. The main concept that connects everything we did this week is concentration is related to molarity and we used this knowledge to assist us in our lab.

            The first activity that we did was complete a lecture quiz on molarity. What we learned from this lecture quiz is the equation: Molarity (M)= moles of solute/volume of solution in liters. This concept is very important to understand and connects with the idea of dilution that we saw in the lab. In the lab we saw this relationship because the moles of solute (the blue dye) would decrease as we increased the amount of water in the solution and the solution became much more diluted. The next important concept that was learned from the lecture quiz is that volume is temperature dependent. This has to do with molarity and when temperature does go up the volume also goes up and the molarity will then decrease. We also learned about the different kind of pippetes, their usages, and how they affect how many moles of a solution and the volume of the solution depending on what kind of pipette you’re using.

            After looking at the lecture quiz, we worked with some stoich problems. We used the knowledge that we previously had on moles, molar mass, and the relationship between grams and moles. With this knowledge we were able to solve a lot of problems involving these concepts. The equation that we used a lot was moles x molar mass=weight. By using this equation, we were able to see the relationship between moles, mass, weight, and atoms in the many problems we did.

            The last thing we did this week was a lab looking at the relationship between concentration and absorbency. We performed this lab by first altering the concentration of many different solutions of blue #1 dye and water and finding the absorbency of these varying solutions. Then we looked at the different absorbency levels of blue #1 dye in Powerade and G2 to find the concentration of blue #1 dye in these solutions. We developed a linear equation between these two variables and were able to perform calculations with this knowledge. This lab connected everything we learned from the lecture quiz and stoich problems.

            We came to know and understand these concepts through experimentation and doing problems in class. I am still a little bit confused on Beer’s Law and there was a problem in the lab that required us to use this law. I would just like to grasp a better understanding of this relationship. I thought I did a good job in participating in the activities we did this week and this gave me a really good understanding of what we are doing. On a scale of 1-5, I would say I am at about a 4 on this material and I don’t really have any new questions to ask about the material.