A Level Chemistry Enthalpy Definitions

Questions and Answers

What is the standard enthalpy change of reaction?

The enthalpy change that accompanies a reaction in the molar quantities shown in a chemical equation under standard conditions, with all products and reactants in their standard states.

What is the standard enthalpy change of formation?

The enthalpy change that takes place when one mole of a compound is formed from its elements under standard conditions, with all products and reactants in their standard states.

What is the standard enthalpy change of combustion?

The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions, with all products and reactants in their standard states.

What is average bond enthalpy?

The energy required to break one mole of a specified type of bond in a gaseous molecule. Signup and view all the answers

What is lattice enthalpy?

The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions. Signup and view all the answers

What is the standard enthalpy change of atomisation?

The enthalpy change that takes place for the formation of one mole of gaseous atoms from the element in its standard state under standard conditions. Signup and view all the answers

What is first ionisation energy?

The enthalpy change required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions. Signup and view all the answers

What is first electron affinity?

The enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions. Signup and view all the answers

What is the standard enthalpy change of solution?

The enthalpy change that takes place when one mole of a solute completely dissolves in a solvent under standard conditions. Signup and view all the answers

What is the standard enthalpy change of neutralisation?

The enthalpy change that accompanies the reaction of an acid by a base to form one mole of H2O (l), under standard conditions, with all products and reactions in their standard states. Signup and view all the answers

What is enthalpy change of hydration?

The enthalpy change that accompanies the dissolving of gaseous ions in water to form one mole of aqueous ions. Signup and view all the answers

Study Notes

Standard Enthalpy Changes

Standard Enthalpy Change of Reaction: Measures the enthalpy change for a reaction occurring in equilibrium with the quantities outlined in the chemical equation and all substances in their standard states.
Standard Enthalpy Change of Formation: Represents the enthalpy change when one mole of a compound is synthesized from its basic elemental forms under standard conditions.
Standard Enthalpy Change of Combustion: Refers to the enthalpy change when one mole of a substance undergoes complete reaction with oxygen under standard conditions.

Types of Enthalpy

Average Bond Enthalpy: Indicates the average energy required to break one mole of specific bonds in gaseous molecules, reflecting bond stability.
Lattice Enthalpy: Denotes the enthalpy change during the formation of one mole of ionic compound from its gaseous ions, important for understanding ionic compounds' stability.

Additional Enthalpy Concepts

Standard Enthalpy Change of Atomisation: Illustrates the enthalpy change necessary for converting one mole of an element in its standard state to one mole of gaseous atoms.
First Ionisation Energy: Represents the energy needed to remove one electron from each atom in a mole of gaseous atoms to create gaseous 1+ ions.
First Electron Affinity: Defines the enthalpy change when one electron is added to each atom in a mole of gaseous atoms, resulting in gaseous 1- ions.

Solution and Neutralisation Enthalpy

Standard Enthalpy Change of Solution: Engages the enthalpy change that occurs when one mole of solute dissolves in a solvent completely under standard conditions.
Standard Enthalpy Change of Neutralisation: Involves the enthalpy change during the acid-base reaction that produces one mole of water, with all participants in their standard states.
Enthalpy Change of Hydration: Describes the enthalpy change when gaseous ions dissolve in water to form one mole of aqueous ions, relevant for understanding solubility processes.

Description

Explore essential definitions related to enthalpy changes in chemistry with these flashcards. Perfect for A Level Chemistry students, this quiz covers standard enthalpy changes of reaction and formation, providing clear explanations to enhance your understanding.