To calculate the enthalpy change of the dissolution, we first need to determine the heat absorbed by the solution q . We can do this using the formula:q = mcTwhere m is the mass of the solution, c is the heat capacity, and T is the change in temperature.First, we need to find the mass of the solution. We know that the mass of sodium chloride is 5.00 g, and the mass of water is 100.0 mL. Assuming the density of water is 1 g/mL, the mass of water is also 100.0 g. Therefore, the mass of the solution is:m = 5.00 g NaCl + 100.0 g water = 105.0 gNext, we can calculate the change in temperature:T = T_final - T_initial = 28.6C - 25C = 3.6CNow we can calculate the heat absorbed by the solution:q = 105.0 g 4.18 J/gC 3.6C = 1573.32 JSince the dissolution of sodium chloride is an endothermic process, the enthalpy change H will be positive. Therefore, the enthalpy change of the dissolution of 5.00 g of sodium chloride in 100.0 mL of water at 25C is:H = +1573.32 J