How many iron ions (Fe3+) are present in 43.6 g of FeCl3?

Answer 1

Molar mass of FeCl3 = 55.8 + 35.5 x 3 =162.3g/mol

43.6g FeCl3 = 0.269 mol FeCl3 = 1.62 x 10^23 molecules FeCl3

There is one Iron(III) ion per molecule of Iron(III) chloride. Therefore, there are 1.62x10^23 Fe3+ ions in your sample.