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!
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!
