0 6 . 3 0.72 g of magnesium is added to 100 cm 3of hydrochloric acid. The hydrochloric acid is in excess. Calculate the concentration of the magnesium chloride (MgCl2) solution produced in g/dm 3 . Relative atomic mass (Ar): Mg = 24 Relative formula mass (Mr): MgCl2 = 95 [6 marks] Concentration = g/dm

To calculate the concentration of the magnesium chloride solution, we need to follow these steps:

1. First, we need to calculate the amount of MgCl2 produced. Since the hydrochloric acid is in excess, all of the magnesium will react to form MgCl2. The reaction is Mg + 2HCl -> MgCl2 + H2. From the reaction, we can see that one mole of Mg reacts to form one mole of MgCl2.

2. Calculate the moles of magnesium used. We know that the mass of magnesium used is 0.72g and the relative atomic mass of magnesium is 24. So, the moles of magnesium = mass / relative atomic mass = 0.72 / 24 = 0.03 moles.

3. Since one mole of Mg produces one mole of MgCl2, the moles of MgCl2 produced is also 0.03 moles.

4. Now, we need to convert the moles of MgCl2 to grams. We know that the relative formula mass of MgCl2 is 95. So, the mass of MgCl2 = moles * relative formula mass = 0.03 * 95 = 2.85g.

5. Finally, we can calculate the concentration of the MgCl2 solution. We know that the volume of the solution is 100 cm3, which is equal to 0.1 dm3. So, the concentration = mass / volume = 2.85 / 0.1 = 28.5 g/dm3.

So, the concentration of the magnesium chloride solution produced is 28.5 g/dm3.