Question

What is the heat released when 25 grams of sodium hydroxide (NaOH) crystallizes out of a solution at its freezing point, given the enthalpy of fusion of NaOH is -44.51 kJ/mol? (Molar mass of NaOH = 40.00 g/mol)

Answer 1

First, we need to determine the number of moles of sodium hydroxide  NaOH  in the 25 grams of the sample.moles of NaOH = mass of NaOH / molar mass of NaOHmoles of NaOH = 25 g / 40.00 g/molmoles of NaOH = 0.625 molNext, we will use the enthalpy of fusion of NaOH to calculate the heat released during the crystallization process.Heat released  q  = moles of NaOH  enthalpy of fusionq = 0.625 mol  -44.51 kJ/molq = -27.81875 kJThe heat released during the crystallization of 25 grams of sodium hydroxide is approximately -27.82 kJ.