Chemistry · Chapter 09

💦 Water & Solutions

The universal solvent.

💡 The Universal Solvent

Water (H₂O) dissolves more substances than any other liquid — that's why it's called the universal solvent. The molecule is bent, with partially positive H atoms and a partially negative O atom — making it polar.

When salt dissolves in water:

• Water's positive H ends grab the Cl⁻ ions
• Water's negative O end grabs the Na⁺ ions
• Result — Na⁺ and Cl⁻ scatter into the water, the crystal disappears

A solution = solute (what's dissolved) + solvent (what's doing the dissolving). Concentration tells how much solute is in there. Too much → it stops dissolving (saturated).

Water molecule (H₂O) — bent shape, polar moleculeWikimedia Commons / CC BY-SA 3.0

Distillation apparatus — separating mixtures by boiling pointWikimedia Commons / CC BY-SA 3.0

🎬

Salt Dissolving in Water

Animation

Watch ions break away from the salt crystal and disperse in water. The whole crystal disappears!

🧪

Stir the Solution

Experiment

Hit "Stir" to watch the salt crystal break apart into ions. "Reset" puts it back together.

StateCrystal solid (undissolved)

When salt fully dissolves, you can no longer see it — but the Na⁺ and Cl⁻ ions are still there, swimming around. Taste the water — still salty!