A student plans an experiment to find a value for the molar volume, Vm, of hydrogen gas at room conditions. Hydrogen gas is formed when magnesium reacts with dilute hydrochloric acid, HCl(aq). Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) The student is provided with the following materials: • a piece of magnesium ribbon • 0.50 mol dm⁻³ HCl(aq) • a water trough • a side-arm conical flask • a 250 cm³ measuring cylinder with 2 cm³ graduations for the collection of gas • a 50 cm³ measuring cylinder • a balance that measures to 2 decimal places • access to any necessary laboratory equipment, except gas syringes. The student plans the following procedure. Step 1 Prepare the piece of magnesium ribbon for use in the experiment. Step 2 Measure 30 cm³ of HCl(aq) and pour into a side-arm conical flask. Step 3 Attach the conical flask to a collection system for the hydrogen gas. Step 4 Place the magnesium ribbon in the conical flask. Step 5 Stopper the flask. Step 6 Wait until the final volume of gas collected is constant. Step 7 Wait for an additional 2 minutes, then measure and record the final volume of gas collected.