An equal amount of salt in hot and cold water dissolves at about the same speed. However, the same amount of sugar added into hot and cold water dissolves faster in the hot water than in the cold water.
The solubility of sugar changes much more than the solubility of salt based on the temperature of the water. At 0 degrees Celsius, 35 grams of salt dissolve in 100 milliliters of water. At 100 degrees Celsius, salt's solubility only rises to 39 grams per 100 milliliters of water. The difference in solubility between substances is caused by the different arrangement of the atoms, ions and molecules that make up each substance.