The formation of ash by burning a paper is called a chemical change, why?

This is because when we burn a paper it undergoes the combustion reaction and during the combustion state of the substance it changes from its solid state or liquid state to gaseous state. So the burning of paper is considered as a chemical change as the paper after burning changes into ashes and fumes of gases evolve.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.

answerspecific gravity;