ChemistryExam code: 4CH1
States of Matter
Principles of Chemistry
| Term | Meaning | Example |
|---|---|---|
| Solvent | The substance (usually a liquid) that does the dissolving | Water in seawater |
| Solute | Whatever gets dispersed into the solvent | Sodium chloride in seawater |
| Solution | The single-phase mixture once the solute is fully dispersed | Seawater |
| Saturated solution | Holds as much solute as it can take at the current temperature; further additions stay undissolved | Salt solution sitting over crystals |
| Soluble | Able to dissolve in a stated solvent | Sugar in water |
| Insoluble | Unable to dissolve in a stated solvent | Sand in water |
- Solubility is solvent-specific
- Iodine: insoluble in water, soluble in hexane
- Always quote the solvent when describing a substance as "soluble" or "insoluble"
Exam tip
A saturated solution is defined at a temperature
When you are asked what a saturated solution is (2 marks), give both halves: it holds as much dissolved solute as possible, and it does so at a particular temperature. The temperature is a separate mark and is easy to leave out, yet it is the point: solubility changes with temperature, so a solution that is saturated when cool can dissolve more once it is warmed. Define solute and solvent just as carefully. The solute is the substance that dissolves; the solvent is the substance it dissolves in.