This warming is in addition to carbon dioxide's better-known effect as a heat-trapping greenhouse gas. For scientists trying to predict global climate change in the coming century, the study underscores the importance of including plants in their climate models.
It is a physical change. All phase changes are physical, not chemical. The chemical composition of water does not change when it changes from a liquid to a gas, or for that ma â¦ tter, to a solid.
In case (b), we have a physical change: warm metal is still metal; the fundamental characteristics of the metal are unaltered. Cases (c) and (d) are also examples of physical changes. Water condenses from the gaseous state to the liquid state on the surface of the metal; water is still a pure substance, whether it is in the liquid or gaseous state, and the metal is unchanged chemically by the condensation. Similarly, in case (d), the carbon which is deposited on the metal is still pure carbon.