Chapter 22 - Enthalpy and entropy Flashcards
what is lattice energy?
The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions
what is the standard enthalpy change of formation?
The enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states understand standard conditions
what is standard enthalpy change of atomisation?
The enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state
What is the first ionisation energy?
The enthalpy change accompanying the removal of one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions
what is the second ionisation energy?
The enthalpy change accompanying the removal of one electron from each ion in one mole of gaseous 1+ions to form one mole of gaseous 2+ions
what is the first electron affinity?
The enthalpy change accompanying the addition of one electron to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions
what is the second electron affinity?
The enthalpy change accompanying the addition of one electron to each atom in one mole of gaseous 1- ions to form one mole of gaseous 2- ions
what is the standard enthalpy change of solution?
The enthalpy change that takes place when one mole of a solute dissolves in a solvent
what is the enthalpy change of hydration?
The energy change that accompanies the dissolving of gaseous ions in water to form one mole of aqueous ions
what factors affect lattice enthalpy and hydration?
The ionic size and ionic charge
what effect does increasing ionic radius have on the lattice energy?
The lattice energy is less negative
What is the effect of increasing ionic charge on lattice energy?
Lattice energy becomes more negative
what is the term entropy used for?
The dispersal of energy within the chemicals making up the chemical system
what are the units for entropy?
JK ^-1 mol^-1
In an equation, how can entropy change be predicted?
by comparing the physical states and amount of gas molecules on either side of the equation
what is standard entropy?
The entropy of one mole of a substance under the standard conditions
what is the term feasibility used to describe?
Whether a reaction is able to happen and is energetically feasible
what is free energy change?
The overall change in energy during a chemical reaction
What is free energy change made up of?
The enthalpy change and the entropy change
what is the Gibbs’ equation?
🔺G=🔺H — T🔺S
What must be for a reaction to be feasible?
🔺G < 0
