What is a redox reaction?
A redox reaction is a type of chemical reaction that involves a transfer of electrons between two species.
- What does oxidation and reduction refer to in a redox reaction?
Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons in a redox reaction.
- What is an electrochemical reaction?
An electrochemical reaction is a type of reaction where oxidation and reduction reactions (redox reactions) produce electrical energy or, conversely, an electrical current drives a chemical reaction.
- What are half-reactions in the context of redox reactions?
Half-reactions are the two parts of a redox reaction, one representing oxidation and the other representing reduction. Each shows the electrons that are either lost in oxidation or gained in reduction.
- How is the oxidation number used in redox reactions?
The oxidation number is a tool used to keep track of electrons in an atom during a redox reaction. An increase in the oxidation number indicates oxidation, while a decrease signifies reduction.
- What is a reducing agent and an oxidizing agent?
A reducing agent is a substance that loses electrons (gets oxidized), thereby causing another substance to be reduced. An oxidizing agent is a substance that gains electrons (gets reduced), thereby causing another substance to be oxidized.
- What is the purpose of a salt bridge in an electrochemical cell?
A salt bridge allows the flow of ions between the anode and cathode compartments of a cell, maintaining charge balance as the redox reaction proceeds.
- What’s the difference between a galvanic cell and an electrolytic cell?
A galvanic cell converts chemical energy into electrical energy (spontaneous redox reaction), while an electrolytic cell uses electrical energy to drive a non-spontaneous redox reaction.
- What is the Nernst equation and what does it allow you to calculate?
The Nernst equation allows you to calculate the potential of a half-cell or full-cell reaction under non-standard conditions. It takes into account the reaction quotient and the temperature.
- What is the standard electrode potential?
The standard electrode potential is the potential of a half-cell under standard conditions, with all solutes at 1M concentration and gases at 1 atm pressure.
- Why does the anode have a negative sign and the cathode a positive sign in a galvanic cell?
In a galvanic cell, oxidation occurs at the anode and reduction at the cathode. Because electrons are lost at the anode, it is assigned a negative sign. Since electrons are gained at the cathode, it is given a positive sign.
- What does it mean when a substance is “reduced”?
When a substance is reduced, it gains electrons. In the process, the oxidation number of the substance decreases.
- How does a battery work based on redox reactions?
A battery works by having separate compartments for the oxidation and reduction half-reactions. The flow of electrons from the oxidation half-reaction (anode) to the reduction half-reaction (cathode) generates an electric current that can do work.
- What is meant by the term “redox potential”?
Redox potential, also known as oxidation/reduction potential, refers to the tendency of a chemical species to acquire electrons and thereby be reduced.
- What happens when a redox reaction reaches equilibrium?
When a redox reaction reaches equilibrium, the forward and reverse reactions proceed at the same rate, and the concentrations of the reactants and products remain constant.
- What is the role of a “spectator ion” in a redox reaction?
Spectator ions are ions that exist in the same form on both the reactant and product sides of a chemical reaction. They do not directly participate in the redox reaction.
- How are electrochemical reactions used in real-world applications?
Electrochemical reactions have numerous applications, including batteries, fuel cells, corrosion prevention, electroplating, and the industrial production of many chemicals.
- What does the Faraday constant represent?
The Faraday constant represents the amount of electric charge carried by one mole of electrons.
- What is meant by a “balanced” redox reaction?
A balanced redox reaction means that the number of electrons lost in the oxidation half-reaction equals the number of electrons gained in the reduction half-reaction.
- How is spontaneity of a redox reaction determined?
The spontaneity of a redox reaction can be determined by calculating the standard cell potential (E°cell). If E°cell is positive, the reaction is spontaneous. If it is negative, the reaction is non-spontaneous.
