Chemistry Kinetics and Equilibrium Flashcards

These flashcards cover key vocabulary and concepts from the Kinetics and Equilibrium lecture, including collision theory, enthalpy, activation energy, and Le Chatelier's Principle.

Collision Theory Factors (Reaction Rate)

For the highest reaction rate, factors such as high concentration (e.g., $3.0\,M\,HCl$ instead of $1.0\,M\,HCl$) and high surface area (e.g., zinc powder instead of a zinc strip) are required to increase the frequency of effective collisions.

Catalyst

A substance that increases the rate of a chemical reaction by providing an alternative pathway with a lower activation energy ($E_a$).

Exothermic Reaction

A reaction that releases energy to the surroundings, such as $N_2\,(g) + 3H_2\,(g) \rightarrow 2NH_3\,(g) + 91.8\,kJ$, resulting in a negative change in enthalpy ($\Delta H = -91.8\,kJ$).

Endothermic Reaction

A reaction that absorbs energy from the surroundings, resulting in a positive change in enthalpy ($\Delta H > 0$).

Change in Enthalpy ($\Delta H$)

The difference between the potential energy ($PE$) of the products and the potential energy of the reactants, calculated as $\Delta H = PE_{\text{products}} - PE_{\text{reactants}}$.

Activation Energy ($E_a$)

The minimum amount of energy that must be provided for a chemical reaction to occur.

Chemical Equilibrium

A state in a reversible process where the rates of the forward and reverse reactions are equal, resulting in no net change in the concentration of reactants and products.

Equilibrium Constant ($K_{eq}$)

A numerical value that expresses the ratio between the concentrations of products and reactants at equilibrium, each raised to the power of their stoichiometric coefficients.

Reaction Mechanism

A series of elementary steps (e.g., fast and slow steps) that describe the pathway by which reactants are converted into products.

Reaction Intermediate

A species, such as $N_2O_2$ or $N_2O$, that is produced during one step of a reaction mechanism and consumed in a subsequent step.

Haber Reaction

The industrial process for ammonia production represented by $N_2\,(g) + 3H_2\,(g) \rightleftharpoons 2NH_3\,(g)$, where high pressure favors the formation of $NH_3\,(g)$.

Le Chatelier's Principle (Concentration)

The principle stating that if a chemical system at equilibrium is disturbed by adding a product (e.g., adding $O_2\,(g)$), the system will shift its equilibrium position to the left to consume the added substance.