Unit 12: Kinetics and Nuclear Chemistry—Rates of Reaction
Glossary
- Activated complex
- A chemical species midway between reactant molecules and product molecules.
- Activation energy
- The amount of energy that the reactants need to reach the activated complex.
- Antimatter
- A substance made of antiparticles, such as positrons and antiprotons, which have the same mass but opposite charge as their matter counterparts. When a particle and its antiparticle collide, both are annihilated and energy is released.
- Beta particles
- A high-energy electron produced in the process of nuclear decay (β-).
- Binding energy
- The energy released when a nucleus is broken into individual protons and neutrons.
- Catalyst
- A substance that speeds up a chemical reaction, yet remains unchanged by the chemical reaction.
- Chain reaction
- A reaction in which the products cause further reactions to take place.
- Chemical kinetics
- The study of the rates of chemical reactions.
- Critical mass
- The minimum amount of a substance needed to sustain a fission chain reaction.
- Electron capture
- A type of nuclear decay in which a nucleus captures an electron from a low energy level.
- Elementary steps
- A sequence of simple chemical reactions that make up the mechanism of an overall reaction.
- Enzyme
- A biological catalyst.
- Fission
- The splitting of an atomic nucleus into smaller particles.
- Fusion
- The combining of smaller atomic nuclei to make a larger nucleus.
- Gamma emission
- A type of nuclear decay in which a rearrangement of nuclear particles releases a gamma ray.
- Gamma radiation
- High-energy electromagnetic radiation.
- Half-life (radioactive)
- The time needed for half of a radioactive substance to decay.
- Half-life (kinetic)
- The time required for a reaction to proceed halfway to the products.
- Intermediate
- A chemical species produced by an elementary step of a chemical reaction, and then consumed by another. Intermediates do not appear in the overall chemical equation.
- Mass defect
- The mass lost by nuclear particles when they come together to form a nucleus.
- Net equation
- A chemical equation for a reaction that lists only the reactants and products participating in the reaction.
- Positron
- An antimatter particle equal in mass to the electron but with a positive charge.
- Positron emission
- A type of nuclear decay that releases a positron.
- Potential energy diagram
- A graph that shows the potential energies of reactants, the activated complex, and the products as the reaction progresses. It is also called a reaction coordinate diagram.
- Radiocarbon dating
- A method of determining the age of ancient artifacts by measuring the amounts of different carbon isotopes in the artifact.
- Rate constant
- A multiplicative factor in a reaction's rate law that is related to the approximate rate of the reaction.
- Rate law
- An equation that shows how the rate of a reaction depends on the concentration of the reactants.
- Rate-determining step
- The slowest elementary step in a reaction mechanism.
- Reaction order
- The exponent of a reactant's concentration in a rate law.
- Strong force
- The nuclear force between protons and neutrons that holds a nucleus together.
- Subcritical mass
- An amount of a fissile material below the critical mass.
- Supercritical mass
- An amount of a fissile material above the critical mass.
- X-rays
- The second-highest energy form of electromagnetic radiation, exceeded by gamma rays.
