Question

Joni finds an iron horseshoe and notices how it as a fine layer of red flaky material. On closer examination, it is a fine layer of rust. Given that the horseshoe is 430g, calculate the number of moles of pure iron the original horseshoe had?

Answer 1

You have left a vital piece of information: the initial mass of the horseshoe..........i.e. just after if it was produced.

Explanation:

To a first approx. we know that there are `(430*g)/(55.8*g*mol^-1)~=` `8*mol` of iron...........

But we don't know much of the iron horseshoe has oxidized with respect to its initial mass. Quite probably, this is a negligible amount, but we `"dunno a priori"`.