Lab9_discussion - DISCUSSION/CONCLUSION: (26 pts ) The...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
DISCUSSION/CONCLUSION: (26 pts ) The experiment was designed to illustrate various examples of electrolytic and galvanic cells, demonstrate the relationship between electrochemical potential and spontaneity, and provide experience with basic electrochemistry calculations 1 . In section A-1, 0.249g of copper chloride was added to 50mL of water along with a small piece of solid aluminum foil. Once all of the components were in the solution, the aluminum foil began to oxidize and rust, turning a brown/black color. The substance formed on the aluminum foil was copper solid, which indicated that the reaction occurred spontaneously (no electricity or other catalyst needed to be introduced to spark a reaction) and had a positive ∆E o value. In section A-2, 0.505g KI was added to 50mL of D.I. water along with 2 drops of 0.1% phenolphthalein. The initial pH of the solution, before addition of the graphite electrodes, was 4.85 ([OH - ] i =7.08E-10M). Once the graphite electrodes were created (2 pencils were taped to a 9V battery and connected with electrodes placed directly on the graphite part of the pencils), they were placed in the solution. During the time of reaction (approximately 8 minutes and 15 seconds, or 495 seconds), the solution near one end of the graphite electrode began to turn a purple color, while the solution on the other end turned a yellow color. Eventually, the entire solution turned a darker yellow color. After the 495 seconds, the final pH value of the solution was 9.95 ([OH - ] f =8.91E-05M), indicating the concentration of OH - ions had increased due to the introduction of the electric source to spark the reaction. The ∆[OH - ] value was 8.91E-05M, which, through the mole-ratio calculation, resulted in 2.23E-06mol I 2 being formed in the reaction. Also, 4.46E-06mol electrons were generated during the reaction, because the electric current provided the energy to transfer the
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/21/2010 for the course CHEMISTRY 1312 taught by Professor Bottomley during the Summer '10 term at Georgia Institute of Technology.

Page1 / 4

Lab9_discussion - DISCUSSION/CONCLUSION: (26 pts ) The...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online