°C·kg/mol
Celsius kilogram per mole
Molal constantexact by definition
The Celsius kilogram per mole is numerically identical to the kelvin kilogram per mole, and the factor of 1 is exact. The reason is the absolute-versus-interval distinction: the temperature in a molal constant is always a temperature CHANGE, a depression or an elevation, and a Celsius degree of change is exactly a kelvin of change. No offset ever enters.
Watch out: Textbooks write Kf as 1.86 °C·kg/mol and as 1.86 K·kg/mol interchangeably, and both are correct. This is not sloppiness: the quantity really is the same, because the degree in it is an interval.
| 1 °C·kg/mol | 1 K·kg/mol |
Solvers that use molal constant