SG Chemistry 2A Week 2 Blog

           This week in Chemistry our main focus was scientists and their discoveries in history, a topic I found very interesting to learn about. But before we dove into this, we started the week finishing up and white boarding the last three problems on Unit 4 worksheet 2, which was on Avogadro's hypothesis. 
            Before we went over these problems in class I was very confused by the concept that two volumes of hydrogen chloride were formed from only one volume of hydrogen and chlorine.  The rest of my table was too, so when we displayed our answer we had 6 molecules of hydrogen (having only one atom) and 6 molecules of chlorine (containing 2 atoms) that when combined only had 3 molecules of hydrogen chlorine in each volume, just like shown below.

            We quickly learned, after looking around the room, that there was something not right about this answer. Dr.Finnan showed us that this violates the conservation of mass law.  We then realized that hydrogen must contain 2 atoms in order for this to honor the conservation of mass law as well as Avogadro's hypothesis. When showing our answers for the next question, where two volumes of nitric oxide combined with one volume of oxygen to form two volumes of a reddish-brown gas, we took this knowledge and applied it so that the number of molecules in each volume were equal.

          Transitioning into famous scientists and their discoveries in history we began watching a movie that followed the lives of scientists Antoine Lavoisier and Joseph Priestley. I found this movie was much more interesting than other documentaries because instead of other people talking about Lavoisier's and Priestley's discoveries, there were actors to play the scientists and reenact their experiments. This made it much easier to visualize and with actual lines spoken from the scientist's journals I found it was more realistic.

           The video’s main concept was centered around the discovery of air and oxygen as well as elements and what they are.  Joseph Priestley noticed that when Mercury Calx, a red solid stone, was heated it did more than just turn into mercury, a silver liquid metal, but emit a strange gas also.  He did many experiments with this gas. He collected it and lit a flame in it, observing that it burned much longer and brighter than in normal air, and he also put mice into this gas and regular air and the mouse in this new gas lived much longer. Lavoisier later named this gas oxygen and after conducting an experiment burning a flame in a mixture of oxygen and phlogiston he came to rename phlogiston hydrogen.

           Learning about the way oxygen, the most essential gas for life, and hydrogen were discovered is so exciting to me, and getting to conduct the experiments in Dalton’s playhouse online that these famous scientists also did is very cool.  Online we did three experiments, the mercury calx experiment done by Priestley, the flame experiment done by Lavoisier and the burning of diamonds and coal experiment and recorded our findings.  These interactive experiments really helped me to understand these concepts on a deeper level doing them myself. I really enjoyed learning about the history of chemistry, knowing the background will make my learning much more applied and in depth.