液化是物质由气态变成液态的变化过程,它的发生伴随着放出热量.使气体液化有两种方法:一是降低温度,二是压缩体积.液化广泛地存在于我们的身边,有自然现象,也有人为制造的现象.其中最为常见的是水蒸气的液化.水蒸气是看不见、摸不着、无色、无味的气体,只有当它液化成小水珠后,我们才能看见它.请看下面的事例。 Liquefaction is a process in which a substance changes from a gaseous state to a liquid state. Its occurrence is accompanied by the release of heat. There are two ways to liquefy a gas: one is to reduce the temperature, and the other is to compress the volume. Liquefaction exists widely around us, and there are natural phenomena. There is also the phenomenon of manufacturing. The most common of these is the liquefaction of water vapor. Vapor is an invisible, intangible, colorless, odorless gas. Only after it is liquefied into small droplets can we see it. The following example.