It is a chemical change and a physical change
Light is refracted when it crosses the interface from air to glass in which it moves more slowly.
Since the light speed changes at the interface, the wave length of the light must change too. The wave length decreases as the light enter the medium and the light wave changes direction.
Well since you can only heat your home/water with it and your home stove is less efficient than say the zero-emmisions one in gillete WY. and the distribution cost placed on top of that. you would pay more than the coal-made-electricity. plus you would burn more for the same effect. and coal decomposes in oxygen so that's not EPA condoned anymore. so the answer is. . . none. its more advantageous to just use the electricity
Nitrogen has an outer shell with 5 electrons it needs 3 to make 8 and be stable