To calculate the standard enthalpy change for the dissolution of 3 mol of potassium chloride KCl in 1000 mL of water, we can use the given molar enthalpy of dissolution.Molar enthalpy of dissolution = -17.4 kJ/molWe have 3 mol of KCl, so we can multiply the molar enthalpy of dissolution by the number of moles to find the total enthalpy change:Standard enthalpy change = molar enthalpy of dissolution number of moles Standard enthalpy change = -17.4 kJ/mol 3 mol Standard enthalpy change = -52.2 kJSo, the standard enthalpy change for the dissolution of 3 mol of potassium chloride in 1000 mL of water is -52.2 kJ.