When ammonium chloride (NH₄Cl) is dissolved in water, the solution becomes colder.

a. Is the dissolution of ammonium chloride endothermic or exothermic?

b. What can you conclude about the relative magnitudes of the lattice energy of ammonium chloride and its heat of hydration?

c. Sketch a qualitative energy diagram similar to Figure 14.7 for the dissolution of NH₄Cl.

d. Why does the solution form? What drives the process

Transcribed Image Text:

► FIGURE 14.7 Heat of Hydration and Heat of Solution The heat of hydration is the heat emitted when 1 mol of gaseous solute ions is dissolved in water. The sum of the negative of the lattice energy (which is AHsolute) and the heat of hydration is the heat of solution. Heat of Hydration Energy KF(s) K(g) + F¯(g) AHsolute = -AH lattice AHsolute = +821 kJ/mol K+ (aq) + F¯(aq) AHhydration-819 kJ/mol AHsoln =+2 kJ/mol