To calculate the heat of hydration for the given amount of calcium chloride, we first need to determine the number of moles of calcium chloride in 50 grams.The molar mass of calcium chloride CaCl2 is:Ca = 40.08 g/molCl = 35.45 g/mol but there are 2 chlorine atoms in CaCl2, so we multiply by 2 Molar mass of CaCl2 = 40.08 + 2 35.45 = 40.08 + 70.9 = 110.98 g/molNow, we can find the number of moles of calcium chloride in 50 grams:moles = mass / molar mass = 50 g / 110.98 g/mol = 0.4505 molNow that we have the number of moles, we can calculate the heat of hydration for this amount of calcium chloride using the given heat of hydration value -82.8 kJ/mol :Heat of hydration = moles heat of hydration per moleHeat of hydration = 0.4505 mol -82.8 kJ/mol = -37.3 kJSo, the heat of hydration of 50 grams of calcium chloride when dissolved in 200 mL of water at 25C is -37.3 kJ.