Tina finds a paper covered with a white substance in a chemistry lab. She keeps the paper near the window of the lab and comes back to pick it up after five hours to take it home. She noticed that the white substance had turned grey. a) What could be the most likely substance on the paper that Tina found? b) The substance changed from white to grey. Write the balanced chemical equation for this reaction c) State ONE application of this property of the substance seen in daily life​