The purpose of this experiment was to find out how the amount of Salt present within the Salt-Bridge of a Galvanic Cell alters the amount of electrical energy outputted, whether it be positively or negatively. The hypothesized outcome was that the more Salt used within the Salt-Bridge would result in more electrical energy being created by the Cell.
Galvanic Cells, also called Voltaic Cells, are prototype batteries, which function as scientific models to the real everyday-use battery. This type of model strips a battery to its core, which involves a chemical reaction, involving two substances, a chemical compound willing to lose Electrons, and a chemical compound willing to steal Electrons from the previous compound, inclined to donate an Electron. These compounds are called the Reducing Agent and the Oxidizing Agent, respectively. For this experiment, Zinc in solid form with a liquid form of Zinc Sulfate was used as the Reducing Agent, whereas Copper in solid form used with a liquid form of Copper Sulfate was used as the Oxidizing Agent. When connected by a wire, the Oxidizing Agent will immediately start seizing Electrons, as the Reducing Agent happily supplies them. After a while, the Reducing Agent starts to corrode, due to the extensive loss of Electrons. Its charge becomes extremely positive, and the Oxidizing Agent takes in more and more Electrons, thus making its charge extremely negative. If not controlled, this circuit will eventually fail, depending on the materials used. This is why everyday batteries lose their ability to provide energy after a period of time. Those that are rechargeable use an external source of energy to reassemble the Electrons to the Reducing Agent, and then can be used again for a long period of time before needing to be recharged again. For the purpose of this experiment, the battery was kept non-rechargeable for simplicity. This type of reaction is called a Reducing-Oxidizing Reaction, Redox Reaction for short. In order to keep the Galvanic Cell alive, the charges on both sides of the Cell need to be kept neutral, so the Reducing Agent can constantly supply the Oxidizing Agent with Electrons and the Oxidizing Agent can continue to take Electrons from the other. In order to keep them neutral, Ions need to be supplied. In the experiment, Salt, or NaCl was used as the Ions in the Salt-Bridge, keeping the charges neutral on both sides, and keeping the Cell running. The key to harnessing the Electrons and use them as Direct Current electricity is to separate the Agents, connect them with a conductive material, such as a wire, and a neutralizer, such as the Salt-Bridge, and then the circuit will be completed!
The diagram above shows the setup of this chemical reaction, as the Reducing Agent, in this case, and in the case of the experiment is a solid strip of Copper, and the Oxidizing Agent, in this case, and in the case of the experiment is a solid strip of Zinc. The Copper is the Orange strip on the left, and the Zinc is the Silver-colored strip on the right. In between them, a wire hooked up to a Multimeter measures the electrical energy flowing through the current, from them, the Wattage can be calculated. The solutions in each beaker are Sulfates, specifically, the one with the Copper (on the left) contains Copper Sulfate, and the one with the Zinc (on the right) is filled with Zinc Sulfate. The Blue Bridge in between the beakers is also described as a Salt-Bridge for this experiment, as it is a paper towel soaked with salt water. As previously described, the Salt-Bridge keeps the charge neutral within each beaker, thus allowing the battery an extended life. Once the Copper gets a stable connection to the Zinc through the provided wire, it starts to Oxidize the Zinc, by making it lose Electrons and making its charge more positive, while the Copper’s charge gets increasingly negative. This is where the Sulfates and the Salt-Bridge come into play. After a while, depending on the materials used as the Electrodes of the battery, the output of the energy will slowly decay, and this is due to the extreme loss of Electrons from the Reducing Agent (Zinc), thus not being able to provide the Oxidizing Agent (Copper) with anymore Electrons, and the Oxidizing Agent (Copper) not being able to take up any more Electrons due to the excessive negative charge. This is when the battery would normally die. However, the Salt-Bridge prevents this from happening by constantly providing Ions to counteract the extreme charges, and to neutralize them, keeping the constant source of Electrons and keeping the battery running for a longer period of time. The ions cannot travel by themselves straight into the Zinc and Copper plates, because it needs to be in a liquid state. And salt melts at 801℃, so the only option is to mix it with a liquid, preferably water (H2O), and let the Ions flow through the Sulfates, which allow contact for the Ions, so they can replenish the Electrons within the Zinc and the remove the Electrons within the Copper. Together, this creates a circuit that produces electrical energy from chemical energy. This electrical energy can be used to power small devices, such as light bulbs, and mass production of such devices that are better engineered for efficiency can become the next way to sustainably power the world on a larger level than before.
