Define the following terms: anode, cathode, cell voltage, electromotive force, standard reduction potential.

In electrochemical cells, two primary types of electrodes are crucial: the anode and the cathode. The anode is the electrode where oxidation occurs. This electrochemical reaction involves the loss of electrons. Picture the anode as a 'negative' participant in a tug-of-war, relinquishing electrons into the electrochemical battle. Contrarily, the cathode is where reduction takes place, meaning it's the 'positive' contender gaining electrons.

It's vital to unpuzzle the common misconception that the anode is always negatively charged and the cathode is always positive. In a rechargeable battery during discharge, the anode is negative as it gives away electrons. However, when you recharge the battery, the flow of electrons reverses, and the anode becomes positive. Similarly, the cathode switches charges depending on whether the battery is being used or charged.

Think of cell voltage, or cell potential, as the driving force that pushes electrons from the anode to the cathode through an external circuit. It's the electrical tension between the two poles, and we measure it in volts (V).
When you place a strip of zinc into a copper sulfate solution, you can see cell voltage in action. Electrons move from the zinc, which becomes the anode, to the copper, the cathode. A voltmeter connected to this system would read a positive voltage, indicating a spontaneous reaction. A larger cell voltage means a stronger push for the electrons to move, explaining why high-voltage batteries can power larger devices.

Electromotive force (emf) is often mistaken as a type of force, but it's not a force at all—it's a potential difference. When contemplating emf, envision an ideal battery without any internal resistance. The emf is the maximum voltage such a battery could provide between its terminals. Real-world devices typically operate under conditions that draw current from the battery, causing a slight discrepancy between the emf and the measured cell voltage. It's this 'oomph' that emf adds to drive the electrons through the circuit, overcoming any obstacles like resistance.

Standard reduction potential (SRP), represented by the symbol \(E^0\), is akin to a leaderboard ranking the eagerness of chemical species to gain electrons under standard conditions—that is, at a pressure of 1 atmosphere and a temperature of 298.15 K. The higher or more positive the SRP value, the more likely the species will strut forward and grab those electrons, acting as the cathode. This 'potential' is elective in nature; it decides the outcome of the electrochemical prom king or queen. With SRP charts, chemists can predict the spontaneity of reactions: when comparing two half-cells, the one with higher SRP will tend to be the cathode where reduction happens. And that is the core of how batteries decide who does the hard work of gaining electrons.