Meaning: A treeless grassy plain. Classified under: Nouns denoting spatial position. Hypernyms (prairie is a kind of...): grassland (land where grass or grasslike vegetation grows and is the dominant form of plant life). Instance hyponyms:
In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. For example, the triple point of mercury occurs at a temperature of â38.83440 Â°C and a pressure of 0.2 m Pa.
It is therefore called the triple point of the substance, and it represents the only point in the phase diagram in which all three states are in equilibrium. Point C is the critical point of the substance, which is the highest temperature and pressure at which a gas and a liquid can coexist at equilibrium. The figure below shows what happens when we draw a horizontal line across a phase diagram at a pressure of exactly 1 atm.