Question

What is the enthalpy of dissolution of 10 grams of sodium chloride in 100 mL of water at 25°C, given that the final solution has a concentration of 1 M? (Assume that the specific heat capacity of the solution is 4.18 J/g°C)

Answer 1

To calculate the enthalpy of dissolution of sodium chloride, we need to know the heat of dissolution  H  for sodium chloride. The heat of dissolution for sodium chloride is -3.88 kJ/mol.First, we need to find the number of moles of sodium chloride  NaCl  in 10 grams:Molar mass of NaCl = 58.44 g/molNumber of moles =  mass  /  molar mass  =  10 g  /  58.44 g/mol  = 0.171 molNow, we can calculate the enthalpy change for dissolving 0.171 mol of NaCl:H =  moles of NaCl    heat of dissolution per mole H =  0.171 mol    -3.88 kJ/mol  = -0.664 kJThe enthalpy of dissolution for 10 grams of sodium chloride in 100 mL of water at 25C is -0.664 kJ.