A coffee-cup calorimeter contains 100.0 g of water at 25 °C (c_water = 4.18 J g⁻¹ °C⁻¹).
• Experiment A: Addition of 0.200 g of solid X raises the water temperature by 5.6 °C. (Molar mass of X = 80.0 g mol⁻¹)
• Experiment B: Addition of 0.200 g of solid Y raises the water temperature by 2.1 °C. (Molar mass of Y = 40.0 g mol⁻¹)
Rank solids X and Y by the magnitude of their molar enthalpies of dissolution, from most exothermic to least exothermic.