How do you balance the chemical equation: Fe+H_2O = Fe_3O_4+H_2Fe+H2O=Fe3O4+H2?

1 Answer
Apr 28, 2016

3Fe+4H_2O = Fe_3O_4+4H_23Fe+4H2O=Fe3O4+4H2

Explanation:

The Fe_3Fe3 in Fe_3O_4Fe3O4 on the right implies that there must be some multiple of 33 FeFe on the left side.

Similarly the O_4O4 on the right side implies that there must be some multiple of 44 H_2OH2O on the left side.

(3m)Fe+(4n)H_2O = (p)Fe_3O_4+(q)H_2(3m)Fe+(4n)H2O=(p)Fe3O4+(q)H2

Since
color(white)("XXX")(3m)Fe rarr (m)Fe_3O_4XXX(3m)Fe(m)Fe3O4 (there's no place else for the FeFe to go)
and
color(white)("XXX")(4n)H_2O rarr (n)Fe_3O_4XXX(4n)H2O(n)Fe3O4 (there's no place else for the OO to go)
rArr m=nm=n

Further
color(white)("XXX")(4n)H_2O rarr (q)H_2XXX(4n)H2O(q)H2
rArr q=4nq=4n

Therefore we have
color(white)("XXX")(3n)Fe+(4n)H_2O = (n)Fe_3O_4+(4n)H_2XXX(3n)Fe+(4n)H2O=(n)Fe3O4+(4n)H2

Using the simplest version: n=1n=1 gives
color(white)("XXX")3Fe+4H_2O = Fe_3O_4+4H_2XXX3Fe+4H2O=Fe3O4+4H2