Undergraduate / "Chemistry experiments and an unexpected discovery" - UChicago Essay [3]

It's About You Found Something That You Were Looking for.

An Unexpected Discovery

I loved doing chemistry experiments when I was in Grade 9. At that time, I usually did a lot of experiments and had nermous strange and unexpected results.

One day, I planed to produce cupric nitrate by the reaction of copper and dilute nitric acid in the laboratory (the chemical reaction was: 3Cu+8HNO3=3Cu(NO3)2+2NO↑+4H2O) . I put some copper into a test tube. Then I poured enough dilute nitric acid into the test tube. These two chemicals reacted slowly. At first, I could not see any phenomenon. About 5 minutes later, I saw a few transparent bubbles on the surface of the copper. About 18 minutes later, I found the solution turn slightly blue. I thought as time went by, the copper would disappear and the solution would turn completely blue. So I kept the chemicals reacting together in the test tube and left the laboratory.

The next day, to my surprise, I found the solution was GREEN instead of BLUE. I was confused. As I know, copper ions (Cu2+) are blue.

To find out the reason, I think it's important to compare with the "genuine" cupric nitrate solution. So I took some pure cupric nitrate and dissolved it into distilled water. Then, I saw that the solution was blue. Thus, I was sure that something unknown greened the solution.

According to the chemical reaction, I guessed nitric oxide or nitrogen dioxide (Nitric oxide can be easily oxidized in air to form nitrogen dioxide) may made the solution green. So I separately let the nitric oxide and nitrogen dioxide go through the blue cupric nitrate solution. Finally I found that nitrogen dioxide turned the solution green.

Instead of producing cupric nitrate, I discovered that nitrogen dioxide could turn the cupric nitrate solution green. What an unexpected discovery it was!

Undergraduate / My First Participation in Long Distance Race Yale Supplement Eassy [5]

My First Participation in Long Distance Race

When I was in Grade 10, I loved playing various sports such as swimming, jumping and soccer. Two weeks before my school sports meeting, I had decided to participate in long distance race (1500 meters) instead of my strength: short distance race (100 meters). Although I wasn't good at long distance race, I thought it could improve my stamina as well as lung capacity. Undoubtedly, it was a challenging attempt, but I would try my best to improve myself and win a prize for my class.

At first, I was always out of breath and could not finish the race. After the race, sometimes I would feel tired and a little uncomfortable. In order to succeed, I spent a lot of time practicing and usually asked my PE teacher how to breathe during the race. With my effort, I gradually developed my breathing skills and increased my speed. However, I thought I still had potential. I kept training and hoped I could do well in the race.

As time went by, my school sports meeting came. As the long distance race would start on a very hot afternoon, I would lose plenty of energy and sweat a lot during the race. So I ate a piece of chocolate and drank some soda before the race.

Right now, I was standing at the scratch line with other participants and was ready. As soon as I heard the shot, I ran like an arrow leaving a bow. In the beginning, I ran at a constant speed and followed the pace of major people. Later, however, I began to lose my breath and slowed down. Seeing other participant far in front of me, I lost my fight and wanted to give up. At this time, my classmates cheered me up. They waved their hands and shout, "Zhaozhong, got for it! We are proud of you!" I was inspired and reflected on the skills taught by my PE teacher. I adjusted my breath and increased my steps. I caught up with other participants and even surpassed some of them. I gritted my teeth and kept my position. On the last lap of race, I sprinted with all my strength. As soon as I passed the finish line, my classmates came to support me with their hands. I was so exhausted that I couldn't say any thing! After a while, my classmates told me that I had done a great job and got the tenth place in the race. Although our school just honored top eight participants, I still felt happy to take part in the race.

I benefited a lot from long distance race. Physically, it reinforces my stamina and lung capacity; Mentally, it tests my perseverance and tempers my willpower. Therefore, I believe it is meaningful to take part in long distance race. Up to now, I still often take part in long distance running.