Consider the following chemical equations. Indicate which equation/s represent chemical reactions, and which are just physical change/s.Explain your choice/sand if it is a chemical reaction, write the type of reaction.
I. 2NO(g) + O2(g) -->2NO2(g)
II. CO2(s) --> CO2(g)
III. Pb(NO3)2(aq) + 2AgCl(aq) --> PbCl2(s) + 2AgNO3(aq)