To calculate the amount of heat that needs to be absorbed to crystallize 100 grams of sodium acetate, we first need to determine the number of moles of sodium acetate present in 100 grams. The molecular weight of sodium acetate CH3COONa is:C: 12.01 g/mol x 2 = 24.02 g/molH: 1.01 g/mol x 3 = 3.03 g/molO: 16.00 g/mol x 2 = 32.00 g/molNa: 22.99 g/mol = 22.99 g/molTotal molecular weight = 24.02 + 3.03 + 32.00 + 22.99 = 82.04 g/molNow, we can calculate the number of moles in 100 grams of sodium acetate:moles = mass / molecular weightmoles = 100 g / 82.04 g/mol = 1.219 molesSince the heat of crystallization for sodium acetate is -264 kJ/mol, the amount of heat that needs to be absorbed to crystallize 1 mole of sodium acetate is 264 kJ. To calculate the amount of heat needed to crystallize 1.219 moles of sodium acetate, we can use the following equation:Heat absorbed = moles heat of crystallization per moleHeat absorbed = 1.219 moles 264 kJ/mol = 321.81 kJTherefore, 321.81 kJ of heat needs to be absorbed to crystallize 100 grams of sodium acetate from a saturated solution at 40C.