When something dissolves?

Question

When somehing dissolves does it just mean it has been broken down? I'm having a hard time understanding why sugar is said to dissolve in water and something like flour does not?

Answer 1

Dissolving is where the solvent (water) is able to break the solid into the smallest fragments possible, be they molecules or ions. This is usually accompanied by a net release of energy, as well as an increase in entropy. Where the energetics are not right, for example with flour, then the substance is not broken down, and stays in one lump. Such substances are said to be insoluble.

Answer 2

There are two types of dissolution, one is the ionic kind the other one is non - ionic kind. The ionic kind is like common salt sodium chloride. When Sodium Chloride dissolves in water it splits up into sodium ions and chloride ions. The solution is conductive to electric current. Many inorganic salts, acids & alkalis come under this category.

In the non - ionic type (like sugar) the hydrogen bond present in water comingles with the hydrogen bonds present in sugar and this leads to an affinity between the dissolving substance and water. Most soluble organic compounds including sugars, alcohols, esters etc.) come under this category.

(If in case you dint know Hydrogen bonds are special bonds between Hydrogen and Oxygen and extends even beween two different molecules).

Answer 3

The mechanism of dissolution depends upon the type of the compound . Therefore, ionic compounds are highly soluble in water because of high dipole moment of water and its polar character. Ionic compounds dissolve due to ionization as ions can exist only in the solution state.
Organic compounds dissolve in organic solvents like carbon tetra chloride etc. due to increase in intramolecular distances that means due to penetration by the solvent the molecules of the solute get separated resulting in the more number of free molecules.
In case of dissolution of sugar in water water surrounds molecules of sugar resulting in more number of free sugar molecules. But flour can not be disintegrated to the molecular state by water and hence no dissolution takes place.

Answer 4

You want something more simple?
one substance is bigger then other.
water is a fairly big molecule.
salt can fit between the molecule of water, it can be spit or not.
Or another example, you can take a basket full of soccer balls till the basket is full and then take a bunch a tennis balls and it will fit between the spaces of the soccer balls. Give it a shake,stir then you can even add more tennis balls. then you can add marbles and it will find even smaller space to fit into.
When the basket is completely fill then it would be fully saturated.