Bond Enthalpy and Collision Theory Practice Flashcards

Flashcards covering collision theory, system and surroundings, conservation of energy, bond enthalpies, and enthalpy diagrams based on the lecture transcript.

Collision Theory Requirements

The conditions required for a successful reaction, which include enough energy and the correct origination or urination.

System

The specific part of the universe on which you focus your attention during a chemical or physical process.

Surroundings

Everything else in the universe that exists outside of the defined system.

Heat

Energy that moves from one object to another due to a temperature difference, occurring through collisions and flowing from hot objects to cold objects.

Conservation of Energy

The principle that during any chemical or physical process, the energy of the universe remains the same.

Internal Energy Change Calculation

The sum of heat absorbed and work done on the system minus the sum of heat released and any work done by the system.

Work

Physical movement in a system characterized by a push or a pull.

Enthalpy Diagram

A visual representation used to show the change in enthalpy during a chemical reaction.

Bond Breaking

An endothermic process characterized by a positive $\Delta H$, requiring energy from the surroundings.

Bond Forming

An exothermic process characterized by a negative $\Delta H$, where energy is released to the surroundings.

Average Bond Enthalpy: $H-H$

The energy value of $432\,kJ/mol$ required to break the bond of one mole of hydrogen gas.

Average Bond Enthalpy: $N \equiv N$

The energy value of $945\,kJ/mol$ for the nitrogen-nitrogen triple bond.

Average Bond Enthalpy: $O=O$

The energy value of $498\,kJ/mol$ for the oxygen-oxygen double bond.

Electrolysis Cell Enthalpy

An endothermic reaction because it absorbs more energy from the surroundings when breaking bonds than it releases when forming new bonds.

Activation Energy

The minimum energy that colliding particles must have in order to react; it acts as the barrier that reactants must overcome before products can form.

Enthalpy of Combustion

The enthalpy of reaction ($\Delta H$) for the complete burning of one mole of a substance.

Methane Combustion $\Delta H$

The enthalpy of reaction for the complete burning of one mole of methane, which is $-890\,kJ/mol$.

Thermochemical Equation

A representation of an enthalpy change where the enthalpy is written as part of a chemical equation as a product or a reactant.

Negative Enthalpy Sign

Indicated in a chemical equation when the enthalpy number is written with the products.

Positive Enthalpy Sign

Indicated in a chemical equation when the enthalpy number is written with the reactants.