how thick of a veneer is required if some of the water from the meteorite dissociates and the resulting oxygen is used to oxidize one third of Fe+2 in the outer 800 km of the 6000 km proto earth to Fe3+? Assume that after dirrerentiation the outer 800 km of the proto-earth contains 7.0 wt.% Fe and has a density of 3.4g/cm^3. Use these reactions
H2O -> H2 + 1/2O2
and
2FeO + 1/2O2 -> Fe2O3