CHEMISTRY 5070 · STRUCTURED PRACTICE
Magnesium metal reacts with dilute sulfuric acid to form aqueous magnesium sulfate and hydrogen gas:
Mg(s) + → +
A student adds increasing masses of magnesium ribbon to fixed 50.0 cm³ portions of dilute sulfuric acid and records the mass of anhydrous recovered after evaporating to dryness. The yield graph levels off at Point X (0.96 g Mg added, yielding 4.80 g ).
Explain why the mass of does not increase beyond Point X.
Calculate the concentration of the dilute sulfuric acid used in mol dm⁻³.
Calculate the volume of hydrogen gas evolved at r.t.p. at Point X in cm³.
In a second experiment, 1.50 g of magnesium is added to 50.0 cm³ of the same acid. Calculate the mass of unreacted magnesium remaining.
Total: 10 marks