According to Science Kids, things dissolve faster in hot water because the molecules in hot water move at a greater speed, bumping more frequently against the solute (the item being dissolved). The more frequent bumping against the solute causes it to dissolve quicker in the water.Continue Reading
Hot water has a higher amount of kinetic energy. The increased amount of kinetic energy is what causes the molecules to move faster. A solvent (the item that the solute is dissolved into) dissolves the solute by breaking up both its molecular bonds and the solute's molecular bonds. The molecular bonds in both substances have to be broken so that new molecular bonds can form between the solute and solvent. Once the solvent and solute are combined with molecular bonds, it is known as a solution.
The amount of energy required to dissolve a solute into a solvent depends on what substance the solute is. Solutes with strong molecular bonds require more energy for the bonds to be broken. Weak solutes can dissolve at a lower temperature than strong solutes.
Solutes that do not dissolve in water have nonpolar covalent bonds. Nonpolar covalent bonds have a low electronegativity (tendency to attract electrons) and do not readily form new molecules. Water is a polar molecule that requires another polar molecule to form a new molecule.Learn more about Solutions & Mixtures
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 >
Lipids and water do not mix because lipids are nonpolar molecules without a charge, so they do not attach themselves or bond to charged (polar) water molecules. Only charged polar molecules will attach to other charged molecules.Full Answer >
Oil and water don't mix because of a difference between the molecular structure of both substances which causes like molecules to bind tightly to other like molecules, leading to a quick separation between oil and water when the two are mixed. Oil floats above water because it is less dense. These two factors combine to make the two substances separate easily and behave in a predictable manner.Full Answer >
Oil and water don't mix because water molecules have a small positive charge at one end, and a small negative charge at the other end, so they stick to each other. But oil molecules are without charge, which causes them to be attracted to each other more than water.Full Answer >