Week 1 Blog Entry

            This week, we performed our fist-ever lab. Before the lab, however, we needed some background knowledge in order to ensure the lab went as smoothly as possible. At the beginning of the week, first we practiced some stoichiometry problems from our Brown and LeMay book. Due Monday was also a lecture quiz having to do with dimensional analysis and unit factoring. We had to memorize some conversions, such as how the prefix “nano” meant 10^-9 and “micro” meant 10^-6. We were also introduced to molarity, the equation of which is moles of solute/moles of TOTAL volume. The unit of the solution was to be given in Molars (M). Using the knowledge we got from these lecture quizzes and problems, we were nearly finished in our preparations for our lab. On Wednesday, we received a packet of the experiment we were going to perform and also a colorimeter manual. During class, we went over some of this packet and discussed what wavelength the blue #1 would absorb. At first, much of the class said that it would be wavelengths close to the blue end of the spectrum, due to blue#1 having a blue color. However, the blue#1 was reflecting this light. Since it was reflecting light of shorter wavelengths, this meant that light of longer wavelengths was being absorbed. After reading the experiment packet and writing down the procedure in our notebooks, we started the experiment the next day. We worked together as a class and recorded all of the absorbance values on the board. After the class deemed the values realistic, we calculated the averages and also the molar concentration. In order to find this value, we used Beer’s law with a given k. After we got the concentration of all of the solutions, we used the same formula to find the concentrations of blue #1 in Gatorade and Powerade. Our results showed a higher concentration of blue #1 in Powerade than in Gatorade, because it had a higher absorbance of red wavelength. After the lab, we dealt with some follow-up questions and practiced more stoichiometry. Stoichiometry is a subject that I struggle with a little bit. I used to solve all stoich problems using proportions until I realized that they made it hard for me to organize my units. Now, I’m trying to shift my style into the multiplication with canceling out units. I’m trying to practice stoich problems as much as I can, because I know that they're a very big part of finding measurements in experiments. I feel like it’s one of those subjects that once you get it, it’s something you completely understand. I haven’t really reached that point yet, but I know I’m getting close. I’m trying to tale notes on the dimensional analysis powerpoints to aid me in studying. I have some questions mostly about stoichiometry problems. In the problems I’m given, it’s usually clear what I’m supposed to find out and what I’m given. However, sometimes it’s hard for me to figure out the process that I should use to obtain the final result. I’m never sure if I added an extra step or if I’m missing one. The stoichiometry sheet we received on Friday was actually quite easy for me; I finally got the hang of how all the units should cancel out and I should be left with my desired units.

            Overall, this week has been a very exciting, albeit somewhat challenging one in chemistry. I’m sure there will be many challenges in the future, and I’m ready to face them head-on.