Sugar dissolves more quickly in hot water because the water molecules are moving at a higher rate of speed and break down the sugar more quickly. The hot water contains more kinetic energy, and the more mobile water makes the sucrose molecules in the sugar move faster as well.
As the sucrose molecules move faster, the bonds holding them together become more fragile. The water molecules barge in and connect themselves to the sucrose molecules, creating enough energy to yank sucrose molecules away from their peers and make the dissolution process happen more quickly than it would in water at cooler temperatures.
