Question

Ammonium nitrate (NH4NO3) dissolves spontaneously and endothermically in water. How is this possible?

a) It breaks into ions that are attracted to the water molecules.
b) It releases heat during the dissolution process.
c) It forms a strong bond with water.
d) It repels water molecules.

Answer 1

Ammonium nitrate dissolves spontaneously and endothermically in water due to the increase in disorder during the formation of the solution. This process is used to make instant cold packs by absorbing heat from the surroundings.

Step-by-step explanation:

Ammonium nitrate dissolves spontaneously and endothermically in water due to an increase in disorder that accompanies the formation of the solution. When NH4NO3 dissolves in water, the solute species separate, requiring a greater energy input than is recovered when the solutes are solvated. This process is favored by the increase in disorder and is used to make instant cold packs, absorbing heat from the surroundings and providing a cold compress.