Generally, the freeing point of salt water is -2 ºC.
H2O (water): 18.018 g/mol
NaCL (salt): 58.443 g/mol
Sea water is denser than freshwater
Sea Water on average has a salinity of about 3.5%
Weighted average of the molecular weight: 0.965 * 18.018 + 0.035 * 58.443 = 17.387 g/mol
Please check this calculation as it is just a weighted average.
The freezing point of salt water at a depth of 5,000 feet will definitely be less -2 ºC.
Please help me figure out what temperature salt water would freeze at at a depth of 5,000 feet.