Question

heating of zinc oxide and sublimation of iodine is a chemical reaction??​

Answer 1

Answer:

Heating zinc oxide is physical changes because zinc oxide is a white powder the loss of oxygen makes it reversible chemical change so the oxidation takes place.

Answer 2

Zinc Oxide is originally a white powder. When heated up, it turns yellow but does not decompose and when it is removed from the heat it gradually goes back to its original white color. If you heat it strongly enough to very high temperatures it will sublime without apparent decomposition. The reason for the yellow color is that a minute amount of oxygen evaporates from the lattice (70 ppm) the small number of zinc atoms produce lattice defects that give rise to the color. Doping zinc oxide with minute traces of zinc will give a range of colors, yellow, green brown and red.