What is the heat of solution per mole of oxalic acid MW 126
What is the heat of solution per mole of oxalic acid (MW = 126.07 g/mol ), if a temperature drop of 1.43 K is seen when 1.25 grams of oxalic acid is dissolved in a calorimeter with a constant of 0.305 kJ/K. Oxalic acid crystallizes as a dihydrate and the reported molecular weight (126.07 g/mol) includes these waters of crystallization.
Solution
mass of oxalic acid = 1.25 g
moles of oxalic acid = 1.25 / 126.07
= 9.915 x 10^-3 mol
temperature rise = 1.43 K
Q = Cp dT
= 0.305 x 1.43
Q = 0.436 kJ
delta H sol = - Q / n
= - 0.436 / 9.915 x 10^-3
deltaH = 44.0 kJ/mol
heat of solution = 44.0 kj/mol
