1: Electrochemistry
- Page ID
- 221435
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- 1.1: Redox Reactions and Oxidation Numbers
- Redox reactions occur with changes in oxidation numbers as a consequence of electron transfers
- 1.2: Oxidation-Reduction Half-Reactions
- Chemical reactions in which electrons are transferred are called oxidation-reduction, or redox, reactions. Oxidation is the loss of electrons. Reduction is the gain of electrons. Oxidation and reduction always occur together, even though they can be written as separate chemical equations.
- 1.3: Balancing Redox Equations
- Another way to balance redox reactions is by the half-reaction method. This technique involves breaking an equation into its two separate components - the oxidation reaction and the reduction reaction. Since neither oxidation nor reduction can actually occur without the other, we refer to the separate equations as half-reactions.
- 1.4: The Activity Series- Predicting Spontaneous Redox Reactions
- Single-replacement reactions only occur when the element that is doing the replacing is more reactive than the element that is being replaced. Therefore, it is useful to have a list of elements in order of their relative reactivities. The activity series is a list of elements in decreasing order of their reactivity. Since metals replace other metals, while nonmetals replace other nonmetals, they each have a separate activity series.
- 1.5: Corrosion- Undesirable Redox Reactions
- Corrosion of metals is a serious economic problem. Corrosion occurs as a result of the spontaneous electrochemical reaction, as the metal undergoes oxidation.
- 1.6: Batteries- Using Chemistry to Generate Electricity
- Electrochemical cells used for power generation are called batteries. Although batteries come in many different shapes and sizes there are a few basic types. You won't be required to remember details of the batteries, but some general information and features of each type is presented here. Batteries are one way of producing this type of energy. Many important chemical reactions involve the exchange of one or more electrons, and, therefore we can use this movement of electrons as electricity.
- 1.7: Standard Reduction Potentials and Batteries
- Assigning the potential of the standard hydrogen electrode (SHE) as zero volts allows the determination of standard reduction potentials, E°, for half-reactions in electrochemical cells. As the name implies, standard reduction potentials use standard states (1 bar or 1 atm for gases; 1 M for solutes, often at 298.15 K) and are written as reductions (where electrons appear on the left side of the equation).
- 1.8: Cell Notation and Conventions
- Rather than drawing a complete diagram like the figures in the Galvanic Cells section, it is convenient to specify a galvanic cell in shorthand form.
- 1.9: Cells at Non-Standard Conditions
- The voltage of a cell at non-standard state is modified by the relative concentrations of the reactants and products. That is, the cell emf depends on the reaction quotient, Q . The Nernst equation allow for calculating the potential of a non-standard galvanic cell. It is frequently more useful to use the measured voltage to detect the concentration of one of the species.
- 1.10: Electrolysis- Using Electricity to Do Chemistry
- Galvanic cell produce electricity from chemical reactions. Some reactions will, instead, use electricity to get a reaction to occur. In these reactions, electrical energy is given to the reactants causing them to react to form the products. These reactions have many uses. For example, electrolysis is a process that involves forcing electricity through a liquid or solution to cause a reaction to occur. Electrolysis reactions will not run unless energy is added to the system.