Final answer:
An aqueous magnesium chloride solution is created by dissolving 5.79 grams of MgCl2. The van 't Hoff factor for MgCl2 solutions is often slightly less than the theoretical value due to real-world interactions. Magnesium chloride is instrumental in producing magnesium metal from seawater.
Step-by-step explanation:
An aqueous magnesium chloride solution is made by dissolving 5.79 grams of magnesium chloride (MgCl2) in water. This compound is often a product in chemical reactions, and it's important to understand the properties of the resulting solution. For instance, if we look at the van 't Hoff factor, we find that for a 0.050 m solution of MgCl2, which has a measured freezing point depression of -0.25°C, the factor is calculated to be around 2.7. This is slightly less than the ideal value of 3 because in real solutions, ions may associate or solvents may affect the dissociation.
Magnesium chloride also plays a role in the preparation of magnesium metal from sea water, which involves initially precipitating Mg(OH)2 by adding Ca(OH)2. Additionally, when Mg(OH)2 reacts with HCl(aq), it produces an aqueous solution of MgCl2 and water as the byproducts. For educational exercises, calculations often involve figuring out the amounts of reactants or resulting pH under certain conditions, which can deepen the understanding of chemical equilibria and solubility product constants (Ksp).