Adding 5.44 g of NH₄NO₃(s) to 150.0 g of water in a coffee-cup calorimeter (with stirring to dissolve the salt) resulted in a decrease in temperature from 18.6°C to 16.2°C. Calculate the enthalpy change for dissolving NH₄NO₃(s) in water, in kJ/mol. Assume the solution (whose mass is 155.4 g) has a specific heat capacity of 4.2 J/g ∙ K. (Cold packs take advantage of the fact that dissolving ammonium nitrate in water is an endothermic process.)

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