BTU/(lb-mol·°R)
BTU per pound-mole Rankine
Molar entropyexact by definition
The BTU per pound-mole Rankine is exactly 4.1868 J/(mol·K), the unit of US chemical engineering entropy and molar heat capacity tables. The gas constant in it is 1.986, which is the same number chemists know as 1.987 cal/(mol·K).
| 1 BTU/(lb-mol·°R) | 4.1868 J/(mol·K) |
Where the unit came from
That the factor comes out at exactly 4.1868 is not chance: 4.1868 J is the international-table calorie, and the BTU and the IT calorie were defined from the same water-based convention. The imperial molar entropy unit and the calorie-based one are the same unit wearing different clothes.
Solvers that use molar entropy