Vapor (Paperback)

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A vapor (American spelling) or vapour (see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature. This means that the vapor can be condensed to a liquid or to a solid by increasing its pressure, without reducing the temperature. For example, water has a critical temperature of 374 C (or 647 K) which is the highest temperature at which liquid water can exist. In the atmosphere at ordinary temperatures, therefore, gaseous water is known as water vapor and will condense to liquid if its partial pressure is increased sufficiently.