| Term | Definition |
|---|---|
| catalyst | A substance that increases the rate of a chemical reaction without being consumed in the reaction. |
| kinetics | The study of the rate at which a chemical reaction occurs and the factors that influence this rate. |
| product concentrations | The amount of products formed in a given volume as a reaction progresses. |
| reactant concentration | The amount of a reactant present in a given volume of solution, typically expressed in molarity (mol/L). |
| reaction rate | The speed at which reactants are converted to products per unit of time in a chemical reaction. |
| stoichiometry | The quantitative relationship between reactants and products in a balanced chemical equation that determines the rates of change of their concentrations. |
| surface area | A factor that influences reaction rate by affecting the contact between reactants, particularly in heterogeneous reactions. |
| temperature | A factor that influences reaction rate by affecting the kinetic energy and collision frequency of reactant molecules. |
| Term | Definition |
|---|---|
| activation energy | The minimum energy required for reactants to overcome the energy barrier and proceed to products in a chemical reaction. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| energetics | The energy-related properties and changes associated with chemical reactions and processes. |
| multistep reaction | A chemical reaction that proceeds through two or more elementary steps rather than occurring in a single step. |
| overall energy change | The difference in total energy between reactants and products in a chemical reaction; also known as the enthalpy change (ΔH). |
| reaction energy profile | A diagram that plots energy versus reaction progress, showing the activation energy and energy changes for each step in a multistep reaction. |
| reaction mechanism | The sequence of elementary steps that describes how a reaction proceeds at the molecular level. |
| Term | Definition |
|---|---|
| acid-base catalysis | A catalytic mechanism in which a catalyst facilitates a reaction by transferring a proton to or from a reactant or intermediate. |
| activation energy | The minimum energy required for reactants to overcome the energy barrier and proceed to products in a chemical reaction. |
| catalyst | A substance that increases the rate of a chemical reaction without being consumed in the reaction. |
| covalent bonding | A chemical bond formed by the sharing of electrons between atoms. |
| effective collisions | Collisions between reactant molecules that occur with sufficient energy and proper orientation to result in a reaction. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| enzyme | A biological catalyst that speeds up chemical reactions by binding to reactants and lowering the activation energy. |
| rate-determining step | The slowest elementary step in a reaction mechanism that controls the overall rate of the reaction. |
| reaction coordinate | A diagram or pathway showing the energy changes that occur as reactants are converted to products during a reaction. |
| reaction intermediate | A species that is produced in one elementary step of a reaction mechanism and consumed in a subsequent step, not appearing in the overall reaction. |
| reaction mechanism | The sequence of elementary steps that describes how a reaction proceeds at the molecular level. |
| surface catalysis | A catalytic process in which reactants or intermediates bind to or form covalent bonds with a solid surface, creating new reaction pathways. |
| Term | Definition |
|---|---|
| initial rates method | An experimental technique for determining reaction order by comparing the initial rates of a reaction under different initial concentrations of reactants. |
| overall order | The sum of all the individual reaction orders (powers) for each reactant in the rate law expression. |
| rate constant | The proportionality constant in a rate law expression that relates reaction rate to reactant concentrations; its value depends on temperature. |
| rate law | A mathematical expression that relates the reaction rate to the concentrations of reactants, with each concentration raised to a power (order). |
| reactant concentration | The amount of a reactant present in a given volume of solution, typically expressed in molarity (mol/L). |
| reaction order | The power to which the concentration of a reactant is raised in the rate law expression; indicates how the reaction rate depends on that reactant's concentration. |
| reaction rate | The speed at which reactants are converted to products per unit of time in a chemical reaction. |
| Term | Definition |
|---|---|
| first order reaction | A reaction whose rate depends on the concentration of one reactant raised to the first power; characterized by a linear plot of ln[A] versus time. |
| half-life | The time required for the concentration of a reactant to decrease to half its initial value; for first order reactions, the half-life is constant and independent of initial concentration. |
| radioactive decay | The spontaneous process by which unstable atomic nuclei emit radiation and transform into more stable forms; follows first order kinetics. |
| rate constant | The proportionality constant in a rate law expression that relates reaction rate to reactant concentrations; its value depends on temperature. |
| rate law | A mathematical expression that relates the reaction rate to the concentrations of reactants, with each concentration raised to a power (order). |
| reaction order | The power to which the concentration of a reactant is raised in the rate law expression; indicates how the reaction rate depends on that reactant's concentration. |
| second order reaction | A reaction whose rate depends on the concentration of one reactant raised to the second power, or on the concentrations of two reactants each raised to the first power; characterized by a linear plot of 1/[A] versus time. |
| zeroth order reaction | A reaction whose rate is independent of the concentration of reactants; characterized by a linear plot of [A] versus time. |
| Term | Definition |
|---|---|
| collision | The event in which reactant particles come together with sufficient energy and proper orientation to form products. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| rate law | A mathematical expression that relates the reaction rate to the concentrations of reactants, with each concentration raised to a power (order). |
| stoichiometry | The quantitative relationship between reactants and products in a balanced chemical equation that determines the rates of change of their concentrations. |
| Term | Definition |
|---|---|
| activation energy | The minimum energy required for reactants to overcome the energy barrier and proceed to products in a chemical reaction. |
| bond-breaking | The process of breaking chemical bonds in reactant molecules during a collision. |
| bond-making | The process of forming new chemical bonds to create product molecules during a collision. |
| collision frequency | The number of collisions between reactant particles per unit time. |
| collision orientation | The spatial arrangement and relative positioning of reactant molecules during a collision, which determines whether bonds can rearrange in the required manner. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| Maxwell-Boltzmann distribution | A curve that describes how particle energies are distributed in a sample at a given temperature, used to estimate the fraction of collisions with sufficient energy to produce a reaction. |
| particle energy distribution | The range and frequency of different energy levels among particles in a system at a given temperature. |
| successful collision | A collision between reactant particles that has both sufficient energy to overcome activation energy and proper orientation to allow bond rearrangement. |
| Term | Definition |
|---|---|
| activation energy | The minimum energy required for reactants to overcome the energy barrier and proceed to products in a chemical reaction. |
| Arrhenius equation | A mathematical relationship that describes how the rate of an elementary reaction depends on temperature and activation energy. |
| bond-breaking | The process of breaking chemical bonds in reactant molecules during a collision. |
| bond-making | The process of forming new chemical bonds to create product molecules during a collision. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| overall energy change | The difference in total energy between reactants and products in a chemical reaction; also known as the enthalpy change (ΔH). |
| reaction coordinate | A diagram or pathway showing the energy changes that occur as reactants are converted to products during a reaction. |
| reaction energy profile | A diagram that plots energy versus reaction progress, showing the activation energy and energy changes for each step in a multistep reaction. |
| transition state | The highest energy point on a reaction energy profile, representing the arrangement of atoms at the peak of the activation energy barrier. |
| Term | Definition |
|---|---|
| balanced chemical equation | A chemical equation where the number of atoms of each element is equal on both the reactant and product sides. |
| catalyst | A substance that increases the rate of a chemical reaction without being consumed in the reaction. |
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| product | Substances formed as a result of a chemical reaction. |
| reactant | Substances that are consumed in a chemical reaction to form products. |
| reaction intermediate | A species that is produced in one elementary step of a reaction mechanism and consumed in a subsequent step, not appearing in the overall reaction. |
| reaction mechanism | The sequence of elementary steps that describes how a reaction proceeds at the molecular level. |
| Term | Definition |
|---|---|
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| irreversible | A reaction step that proceeds in only one direction and does not reverse under the reaction conditions. |
| molecularity | The number of molecules that participate in an elementary step. |
| rate law | A mathematical expression that relates the reaction rate to the concentrations of reactants, with each concentration raised to a power (order). |
| rate-determining step | The slowest elementary step in a reaction mechanism that controls the overall rate of the reaction. |
| reaction mechanism | The sequence of elementary steps that describes how a reaction proceeds at the molecular level. |
| Term | Definition |
|---|---|
| elementary reaction | A single-step reaction that represents one molecular event in a reaction mechanism, with a specific rate law determined by its molecularity. |
| pre-equilibrium approximation | A method used to derive a rate law when a fast elementary step precedes a slow step, assuming the fast step reaches equilibrium quickly. |
| rate law | A mathematical expression that relates the reaction rate to the concentrations of reactants, with each concentration raised to a power (order). |
| rate-determining step | The slowest elementary step in a reaction mechanism that controls the overall rate of the reaction. |
| reaction mechanism | The sequence of elementary steps that describes how a reaction proceeds at the molecular level. |