Blog #2

September 21-25, 2015

The main ideas that we learned this past week were how theories were formed by different philosophers like Democritus and Dalton, how iodine was discovered, deriving formulas for different masses of elements, and comparing different element levels of the same or different substances.
Democritus reasoned that if you take a stone and cut it into smaller and smaller pieces, at some point it will be too small to cut anymore. He called these very small pieces atomos, which means indivisible, and said that can’t be destroyed. This theory sparked interest in other philosophers and helped explain the physical aspect of the world. Later John Dalton discovered that water could be in a gas and solid. The gas could mix with the air but, ice could not. His theory was composed of four basic concepts that are, all matter has atoms, all atoms in a given element are the same, chemical reactions combine atoms not destroy them, and elements react in whole number ratios when forming compounds. These different theories and concepts were used to inspire and question other scientists to find more about the world they didn’t know.
The next topic was how Iodine was discovered. Nicolas Clement and Charles Bernard Desormes reported a new discovery that was found in seaweed. It gave off a purple vapor, created crystals, and was in a solid form. They thought that he had many similarities to the substance chlorine. A man named Joseph-Louis Gay-Lussac reviewed the scientists experiments, and names then substance “iode” which comes from an ancient Greek word for purple. A scientist with the name Andre-Marie Ampere had a hold of the substance from Clement and Bernard and showed the famous scientist Davy it. Davy studied the substance and ended up calling it its English name Iodine, which is now an element on our periodic table to this day.
We then worked on a worksheet that had us derive formulas for different masses of elements. We were given two compounds, Compound A and Compound B, and were told to find the ratio of it the masses of two elements that made the compound. We compared the ratios to see what the difference was between them, and expressed them as improper fractions. We were given different hypothesis to draw particle diagrams for. Hypothesis one dealt with us using the improper fractions we had previously derived, which helped us decide how many particles of each element should be in it. In hypothesis two we had to take in consideration that the atoms of the element oxygen would be heavier than carbon by the ratio of compound A. Below is what this problem looked like.

Lastly, we did a worksheet on looking at the elements in the substance sucrose. We were given the masses of each element that is in it and found the percent mass each element took up of the substance. Then there was another chemical analysis done that consisted of a heavier sample of pure sugar cane with the same elements in it, just consisting more mass. We found the percentages again which came out to be the exact same as the sucrose percentages were. We found that both of these were sucrose.

This helped explain the Law of Definite proportions. When you have the same proportion just using different masses, it can still be the same substance, since the percentages and ratios would still be the same.

 All of the theories  that were derived in history are what we use today. The basic compound, elements, and mixtures, that we  use everyday for science, is what helped further our knowledge in even more new discoveries. I think I learned a lot of new interesting material this week that I had no clue about. Reading about Iodine and the different theories, opens my eyes and shows me that these laws we take into consideration when exploring science were derived from scratch by some very talented scientists.