! the cooling curve below represents the cooling of a sample of gas. according to the cooling curve, what phase(s) would you expect to observe when the substance is at a temperature of 375 kelvin?

According to the cooling curve given above, at temperature 275K, the phases that will be observed is LIQUID AND SOLID.
The flat points on the graph represent the points where phase changes are taking place.The beginning of the first flat point represent the point where the gas become liquid, the extreme end of this point indicate the point where the liquid has started turning to liquid and that is the point of 275K. Thus at that point both phases are present. 

Ithink is a because if say increased in electronegativity