You have a badly tarnished silver teapot. The tarnish is a result of the silver metal reacting with the oxygen in the air according to 4Ag(s)+O2(g)→2Ag2O(s),ΔH=-62.2kJ/mol
You carefully clean the teapot and then, out of curiosity, you weigh it. The teapot has a mass of 869 g . After some more measuring and calculating, you also determine that 10.0 % of the silver is on the surface and exposed to the air.
If the teapot were once again to become completely tarnished, how much mass Δm is converted to energy?