ELA component

Journal

Copper + Nitric Acid

Mrs.Quintero 10th grade english

For my English component I decided to keep a brief journal about my observations using trials

January 15, 2014 (First Trial)

Today's first try experiment didn't go successful as we expected it to be. With the help of my chemistry teacher's help. My ideas and his combined we assume we didn't put a fair amount of universal indicator, therefore the color of the distilled water in the boiling flask didn't change to deep blue, Since that happened the experiment's results don't match with what is meant to happen. Therefore, it is preferable to do properly again in available time. I learned that not being fast when closing a poisonous gas can catch you off guard and make your eyes watery and cough nonstop. Its a terrible feeling. After this incident I'd probably be more aware of what I'm doing and be more responsible about my health Next time I'll make sure to use the right amount of solution and be more careful and less clumsy.

Febuary 20, 2014 (second trial)

This time we used the proper amounts of universal indicator and sodium hydroxide solution. The only mistake we fortuitously made was adding a larger amount of nitric acid which caused the reaction to go out of control and almost caused a major spill and risk in the classroom. Due to the large amount of nitric acid the gas's speed accelerated causing pressure to increase and pushes the gas with more force to the hole stoppers. This of course leads the liquid to run out of the tip of the Erlenmeyer flask.Deep blue color it has nothing to do with the problem .Cu²⁺ ions; the nitric acid is reduced to nitrogen dioxide, a poisonous brown gas with an irritating odor:

Cu(s) + 4HNO₃(aq) ——> Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

When the copper is first oxidized, the solution is very concentrated, and the Cu²⁺ product is initially coordinated to nitrate ions from the nitric acid, giving the solution first a green, and then a greenish-brownish color. When the solution is diluted with water, water molecules displace the nitrate ions in the coordinate sites around the copper ions, causing the solution to change to a blue color.

Febuary 28,2014.

Surely this experiment trial has went well so far. Unlike the previous disastrous ones. This time the issue wasn't all about the amount we used for the solution, but I am positively sure we added the the correct amount of every substance. The only negative factor is that we didn't get the color I aimed for. I noticed there was no change in pH level or color of the initial solution. The color remained the same: plain white as a pearl.

March 1, 2014

On the day of the STEM festival my experiment was a success during the exhibition. I infer that the previous problem was that I used a miniscule amount of sodium hydroxide solution and nitric acid. In dilute nitric acid, the reaction produces nitric oxide, NO, instead:

3Cu(s) + 8HNO₃(aq) ——> 3Cu(NO₃)₂(aq) + 2NO(g) + 4H₂O(l)

In the following demonstration, a balled-up piece of thin copper wire is added to about 100 mL of concentrated nitric acid; once the copper is added the evolution of nitrogen dioxide occurs quickly. Once all of the copper has reacted, the solution is diluted with distilled water, changing the solution from a dark brown to a pale blue color.

This demonstration can be done with copper in the form of shot, pellets, thicker wire, or bars, but is a great deal slower than with copper wire.