Comparing water potentials
A dilute solution has a higher water potential than a more concentrated solution. Increasing the amount of dissolved solute lowers the water potential.
For pure water at atmospheric pressure, the water potential is 0 kPa. Dissolving solute produces a water-potential value below zero.
Higher water potential
Dilute solutions have values nearer to 0 kPa.
Lower water potential
Increasing solution concentration gives a more negative water-potential value.
| Water-potential value | Interpretation |
|---|---|
| 0 kPa | Pure water at atmospheric pressure |
| Negative but close to 0 kPa | Relatively high water potential |
| More negative | Lower water potential |
Exam Tip: With negative values, compare their position relative to zero: a value further below zero represents a lower water potential. For example, −800 kPa is lower than −300 kPa.