Question

3d(iii) Fe(s)+2HCl(aq)→FeCl2(aq)+H2(g). If 50cm³ of 2.20 mol dm⁻³ HCl reacted completely with iron, calculate the molar mass of the metal (Fe).

Accepted Answer

Mole of HCl = (50/1000)dm³ x 2.20moldm⁻³ = 0.11 mol. Since mole of Fe is half that of HCl (from the balanced equation), mole of iron = 0.5 x 0.11 = 0.055 mol. Molar mass = mass of Fe/mole of Fe = 3.08g/0.055mol = 56 g/mol; thus, the relative atomic mass of iron is 56.

WAEC Chemistry 2010 Theory — Question 24

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