Chemical Kinetics Mind Map

Rate of reaction is the change in concentration of a reactant or product per unit time. For a reactant it is written with a negative sign because its concentration decreases, while for a product it is written with a positive sign because its concentration increases.

Always start by writing the balanced equation, then attach the correct sign and coefficient factor before substituting values.

Rate law expresses reaction rate in terms of molar concentrations of reactants raised to experimentally determined powers. Order is the sum of these powers. Molecularity is the number of reacting species taking part in a single elementary step.

Use experimental data to find order. Use the mechanism or elementary-step statement only when asked about molecularity.

Zero, first, and second order reactions are classified by how rate depends on reactant concentration. Their integrated rate equations relate concentration and time, allowing calculation of rate constant, concentration remaining, or half-life.

Identify the order before choosing the equation. Graph clues are often faster than direct calculation.

The Arrhenius equation relates the rate constant of a reaction to temperature and activation energy: k = Ae^(-Ea/RT), where A is the frequency factor, Ea is activation energy, R is the gas constant, and T is absolute temperature.

For two-temperature problems, use the two-point Arrhenius form and check that activation energy is in J mol^-1 when R = 8.314 J mol^-1 K^-1 is used.

A catalyst increases reaction rate by providing an alternate pathway with lower activation energy. It does not change the overall enthalpy change of the reaction and is regenerated by the end of the reaction.

In an energy profile diagram, draw the catalysed path with a lower peak but the same reactant and product energy levels.