U6 Born Haber Cycles

Given the Born-Haber cycle below, which of the following enthalpy change is not represented by steps a-g

• Enthalpy of formation

• enthalpy of atomization of calcium

• 1st electron affinity of bromine

• 2nd electron affinity of bromine

Identify the enthalpy change represented by letter g.

• enthalpy of formation

• enthalpy lattice of formation

• electron affinity of bromine

• enthalpy of atomisation of zinc

The enthalpy of formation is the enthalpy change under standard conditions

• when one mole of the pure compound is formed from its elements with all reactants and products in their standard state

• when 1 mole of pure substance is completely burned in excess oxygen, under the given temperature and pressure of the reaction

• when 1 mole of H⁺ (aq) ions from acid reacts with 1 mole of OH^- (aq) ions from an alkali to form 1 mole of water under the stated condition of the experiment

• the magnitude of the enthalpy change of a chemical reaction depends only on the difference in the enthalpy content of the products and the reactants, and does not on how the reaction is completed

The enthalpy change when 1 mole of aqueous ions is formed from gaseous ions

• Formation

• Combustion

• Hydration

• Lattice breaking

The enthalpy change when 1 mole of 1+ ions is formed from 1 mole of gaseous atoms.

• Lattice breaking

• Atomisation

• Ionisation

• Formation

Mg (s) --> Mg (g)

• Ionisation

• Combustion

• Formation

• Atomisation

Mg (g) --> Mg+ (g) + e-

• Ionisation

• Combustion

• Formation

• Hydration

Na+ (g) + Cl- (g) --> Na+ (aq) + Cl- (aq)

• Formation

• Solution

• Combustion

• Hydration

Which of the following represents the enthalpy change of solution?

• Cl₂(g) + (aq) ---> 2Cl^-(aq) .

• Mg²⁺(g) ---> Mg²⁺(aq)

• MgCl₂(s) + (aq) ---> Mg²⁺(aq) + 2Cl^-(aq) .

• Mg²⁺(g) + 2Cl^-(g) + (aq) --> Mg²⁺(aq) + 2Cl^-(aq)

What enthalpy change does the number 4 represent?

• Formation

• 1st ionisation energy (Na)

• 1st electron affinity (Na)

• Atomisation (Na)