The diagram shows an electrochemical cell with a gold strip (left) and aluminum glasses (right). In your response, do the following: • Label the cathode and the anode, including the charge on each. • Show the flow of electrons. • Describe what type of electrochemical cell is pictured and what its use is. • What are the oxidation and reduction half-reactions in this cell?
( if the link to the picture does not work, the diagram is of a beaker with a gold strip, and glasses connected to a battery and wires)
This is an electrolytic cell used for (most likely) gold plating. The electrode connected to the positive terminal of the battery will be positive and attract anions from a gold salt rich solution to the electrode to undergo oxidation (=> cathode). The electrode connected to the negative terminal of the battery will be negative and attract cations to that electrode and under go reduction (=>anode). If gold plating, the gold electrode (in a gold-ion rich solution) would be connected to the negative electrode When inserted into the Au^+3 ion rich solution =>
----- Au^+3 +3e^- => Au(s)
To label the cathode and the anode in the electrochemical cell, we first need to understand the direction of electron flow. Electrons always flow from the anode to the cathode.
In the given setup, the gold strip on the left side is connected to the positive terminal of the battery, and the aluminum glasses on the right side are connected to the negative terminal. Therefore, the gold strip acts as the anode, and the aluminum glasses act as the cathode.
Now let's talk about the charges on each electrode. At the anode (gold strip), oxidation takes place, which generates electrons. So, the anode is negatively charged due to an excess of electrons. At the cathode (aluminum glasses), reduction occurs, which consumes the electrons. Therefore, the cathode is positively charged due to the absence of electrons.
Now, let's address the flow of electrons. Electrons flow from the anode (gold strip) to the cathode (aluminum glasses) through an external circuit, powered by the battery. The negative terminal of the battery pushes electrons towards the gold strip, and the positive terminal attracts electrons from the aluminum glasses. This flow of electrons creates an electric current, which powers any devices connected in the circuit.
Based on the setup described, this electrochemical cell is likely a galvanic cell, also known as a voltaic cell. Galvanic cells convert chemical energy into electrical energy through spontaneous redox reactions.
As for the oxidation and reduction half-reactions, here is a possible representation:
At the anode (gold strip):
Oxidation half-reaction: Au(s) ⟶ Au^3+(aq) + 3e^-
At the cathode (aluminum glasses):
Reduction half-reaction: Al^3+(aq) + 3e^- ⟶ Al(s)
In summary, the given electrochemical cell is a galvanic cell, where the gold strip serves as the anode and the aluminum glasses serve as the cathode. Electrons flow from the anode to the cathode, powering an external circuit. The oxidation half-reaction at the anode involves the gold strip being oxidized to Au^3+, while the reduction half-reaction at the cathode involves the reduction of Al^3+ to Al.