Solids dissolve faster in hot water than in cold water because the added heat increases the kinetic energy of the molecules, allowing them to react more quickly with the solid and speeding the chemical reaction. However, certain solvents, such as ionic solutes, have increased polarity at high temperatures, slowing the rate at which the solid dissolves.Know More
When the temperature increases the kinetic energy, the quicker movement of the particles causes less inter-particle attraction, meaning that the molecules of the solvent are less attracted to one another and more likely to be attracted to the molecules in the solute. This change in attraction levels makes it more likely that the molecules of the solvent and the molecules of the solute form a bond, accelerating the dissolving process.
Depending upon the chemical structure of the solute, the increased temperature may also allow the solid to reach and surpass its melting point. At the melting point, the kinetic energy of the molecules increases and the attraction between molecules changes to enable a phase change in the state of matter. As molecules in a liquid state have a lower level of attraction to one another than those in a solid, the melting process can also expedite the dissolving process.Learn more about Solutions & Mixtures
Ammonium nitrate dissolves in water with an endothermic reaction, a chemical reaction that consumes heat rather than releasing it. The temperature of the solution is lower than the starting temperature of either component chemical. Ammonium nitrate's solubility increases as the water temperature rises.Full Answer >
According to the Purdue University College of Science, sugar dissolves easily in water due to the fact that sucrose molecules are held together with weak intermolecular forces. The energy produced when these molecules bond with water is more than enough to offset the energy needed to break those bonds in the first place.Full Answer >
Substances that have ionic molecules or polar molecules generally dissolve in water because water molecules have the ability to surround the those molecules completely and disperse them in solution. Non-polar molecules do not interact with water molecules and are therefore insoluble in water.Full Answer >
A substance dissolves in another because the second substance is able to dissolve the bonds between the molecules of the first. Dissolving a substance and breaking these bonds requires energy, which is why stirring sugar in a glass of water makes the sugar dissolve. The stirring puts energy into the system and causes the bonds to break down.Full Answer >