<Tr> <Td> Heat of vaporization </Td> <Td> 2.27 MJ / kg </Td> </Tr> <Tr> <Td> Heat capacity at 300 K </Td> <Td> 1.864 kJ / (kg K) </Td> </Tr> <P> Water vapor, water vapour or aqueous vapor is the gaseous phase of water . It is one state of water within the hydrosphere . Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice . Unlike other forms of water, water vapor is invisible . Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation . It is less dense than air and triggers convection currents that can lead to clouds . </P> <P> Being a component of Earth's hydrosphere and hydrologic cycle, it is particularly abundant in Earth's atmosphere where it is also a potent greenhouse gas along with other gases such as carbon dioxide and methane . Use of water vapor, as steam, has been important to humans for cooking and as a major component in energy production and transport systems since the industrial revolution . </P>

What is the gaseous state of water called