Energetics

Lattice energy is the energy change when 1mol of an [blank_start]ionic[blank_end] compound is formed from its [blank_start]gaseous[blank_end] ions under [blank_start]standard conditions.[blank_end]

Values of lattice energy are

Enthalpy change of atomisation is the enthalpy change when 1mol of gaseous ions is formed from the [blank_start]element[blank_end] in its [blank_start]standard state.[blank_end]

First electron affinity is the enthalpy change when one [blank_start]e-[blank_end] is added to each [blank_start]gaseous[blank_end] atom in 1 mol to form 1 mol of -1 gaseous [blank_start]ions[blank_end].

What are the factors that affect lattice enthalpy?

The [blank_start]higher[blank_end] the charge on the ion the [blank_start]higher[blank_end] the lattice enthalpy.

Enthalpy of hydration is the [blank_start]heat[blank_end] change when 1 mol of gaseous ions completely dissolve in [blank_start]water.[blank_end]

Label the Born Haber Cycle with the process occurring at each stage.

[blank_start]Enthalpy of Solution[blank_end] is the heat change when 1 mol of an ionic substance dissolves in water

An ionic lattice dissloves in water because water molecules disrupt the attraction between [blank_start]cations[blank_end] and [blank_start]anions[blank_end] in the lattice. Cations become surrounded by the [blank_start]negative[blank_end] part of the water molecules. Anions become surrounded by the [blank_start]positive[blank_end] part of the water molecules.

Enthalpy of Hydration is ...

Entropy is the measure of the [blank_start]disorder[blank_end] of a [blank_start]system[blank_end].

A disorder increases entropy...

Entropy decreases as the solid becomes more complex.

Entropy [blank_start]increases[blank_end] from solid to liquid to gas because molecules become [blank_start]more disordered[blank_end].

There is only a small jump in entropy from ice to water despite the state change as the [blank_start]hydrogen bonding[blank_end] means water is still relatively [blank_start]ordered[blank_end].

Which factors cause a change in entropy

If Gibbs Free Energy is 0 this means

If Gibbs Free Energy is less than 0 this means...

If Gibbs Free Energy is greater than 0 this means...

If delta (the little triangle symbol) G is negative delta S must be [blank_start]positive[blank_end] and delta H [blank_start]negative[blank_end]. The reaction will be spontaneous.

If total entropy is positive the reaction is [blank_start]feasible[blank_end].

total entropy = entropy of [blank_start]surroundings[blank_end] + entropy of [blank_start]system[blank_end]