Lab Number 6

In week 6 lab, our group was able to go down into the Conservative Energy Laboratory and start with our experiment. The experiment wasn't exactly successful, but useful knowledge about the reaction and the process was gained.

We set up the experiment like this:

with one graduated cylinder on each stand and each clamps holding an electrode. It was soon found that this was an incorrect setup for the experiment but the reason why will be explained later. Copper wire was attached to the electrodes using electrical tape and was strung to each pole of the 6 volt battery. On a set time, the wires were applied to the battery and ... not much happened. After over a minute, all that was seen was minor bubbles. 

This indicated that the reaction started, but shortly afterward stopped. This was attempted multiple times but with each successive trial, there was no clear gas production volume. After help from Megan, we decided to add sodium chloride, or salt, to the solution to allow for a faster reaction. This did in fact help, as more bubbles were produced initially, but the reaction still did not continue. 

After scratching our heads and searching for possible answers, the solution struck us near the end of the lab time. We needed to complete the circuit not electrically, but chemically. This could be done in two ways. One being a salt bridge which maintains charge balance by allowing electrons to flow from anode to cathode and around the battery again. The reason why the reaction wasn't continuing was because the air was not able to transfer electrons throughout the two systems. By completing this circuit, the reaction should progress. 

An example salt bridge

The other way the reaction could continue is if we submerged the entire system in a salt-water solution. This makes the surrounding salt-water the salt bridge in which electrons could flow, therefor driving the reaction. 

Kind of like this, in a way.

The sodium chloride used would be a catalyst for the reaction, in result speeding it up. There is concern that chlorine gas would be produced, but this is a chance that we would have to take.  

With this knowledge, we will get into the lab on our own time this week to complete the experiment before lab Friday. This will be done to discover which electrode is the most efficient.