For example, water changes into ice when temperature is lowered, and increasing the temperature reverses this process. Conversely, when heating water, it converts into steam, and lowering its temperature reverses the process. When the conditions are such that forward (represented by ) and backward (represented by ) reactions can both occur to a noticeable extent, the process is described as a reversible reaction. ... A chemical is a substance obtained by a chemical process or used for producing a chemical effect. ... From the published data (as well as their own experiments), they we...