Molar mass of iron(III) oxide is 160g/mol
160g ----------- of iron(III) oxide is ---------------- 6.02*10²³molecules
79g ----------- of iron(III) oxide is ---------------- x
x = [6.02*10²³*79g]/160g ≈ <u>2.97*10²³ molecules</u>
An A horizon is a mineral horizon, It forms at the surface as topsoil. O horizon turns eventually into topsoil
