Chemistry - Thermochemistry Question with Solution | TestHub
Carefully observe the given diagrams which indicates standard enthalpy of formation of different states of one mole Mg and 2 mole Cl atom and match the entries in column A and B provided.
List - I | List - II |
|---|---|
(A) | (P) - 1900 kJ/mole |
(B) | (Q) + 460 kJ/mole |
(C) | (R) - 625 kJ/mole |
(D) | (S) + 2510 kJ/mole |
Options:
Answer:
Solution:
(A) (Q): The individual standard enthalpy of formation for Mg²⁺(aq) is calculated using standard reference values to be .
(B) (R): The standard enthalpy of formation for Cl⁻(aq) is determined from the total formation energy of the solution, giving .
(C) (P): Enthalpy of hydration for Mg²⁺(g) is the difference between the levels at and , which equals .
(D) (S): Lattice enthalpy magnitude is the energy gap between gaseous ions at and the solid crystal at , which equals .