Here's how it works:
* Water molecules are polar: This means they have a slightly positive end (near the hydrogen atoms) and a slightly negative end (near the oxygen atom).
* Many substances are also polar or ionic: Polar substances have unevenly distributed charges, while ionic substances are composed of charged ions.
* Opposites attract: The positive ends of water molecules attract the negative ends of polar or ionic substances, and vice versa. This attraction breaks apart the bonds holding the substance together, causing it to dissolve.
Example: Table salt (NaCl) is an ionic compound. The positive sodium ions (Na+) are attracted to the negative oxygen end of water molecules, while the negative chloride ions (Cl-) are attracted to the positive hydrogen ends. This interaction pulls the salt apart, causing it to dissolve in water.
Not all substances dissolve in water. Nonpolar substances like oil lack the uneven charge distribution that allows them to interact with water molecules. Therefore, oil and water don't mix.
