这两个词有差异,不可通用。“蒸气”的外延比“蒸汽”大,“蒸气”包括“蒸汽”。“蒸气”的“气”指各种气体,如“毒气”“煤气”等;泛指液体或固体(如水、汞、苯、碘)因蒸发、沸腾或升华而变成的气体,都可以叫“蒸气”。“蒸汽”是特指水加热到沸点所变成的水汽,气态的水。“ There are differences between these two words, not universal. The extension of “steam” is larger than “steam” and “steam” includes “steam”. The “gas” of “steam” refers to all kinds of gases, such as “gas”, “gas”, etc .; refers to the liquid or solid (such as water, mercury, benzene, iodine) due to evaporation, boiling or sublimation of the gas can be called “Steam.” “Steam” refers to the water heated to the boiling point of the water vapor, gaseous water. "