Summary
A solution is a homogeneous mixture of two substances: the solute, which is in the smaller amount and dissolves, and the solvent, which is in the larger amount and dissolves it. Salt water is a solution: salt is the solute and water the solvent. The most common solvent is water.
There is a limit to what can be dissolved: when the solvent takes no more solute, the solution is saturated. The amount of solute in a solution is the concentration, and it can be expressed in several ways: in grams per litre (g/L), as a percentage or with molarity. Temperature matters: when hot, more solute usually dissolves.
Key points
- A solution is a homogeneous mixture of solute and solvent.
- Solute: what dissolves (smaller amount). Solvent: what dissolves it (larger).
- The most common solvent is water.
- A saturated solution takes no more solute.
- Concentration measures how much solute there is: g/L, % or molarity.
- Temperature matters: when hot, more usually dissolves.
- A solution is not separated by filtering (the solute is dissolved); you must evaporate.