Answer
-44.42 kJ/mol
Work Step by Step
In part a we found that the NaOH dissolving releases 7.219 kJ of heat. We need to find the molar mass of 6.5g of NaOH.
Na is 22.99 g/mol
O is 16 g/mol
H is 1 g/mol
NaOH is 39.99 g/mol
Therefore, 6.5 g is :
(6.5g) * (1mol/39.99g) = 0.1625 mol
Since 7.219kJ was released, that makes it exothermic and turns 7.219kJ to -7.219kJ.
Then we divide the the heat released by the molar mass to find the kJ/mol :
(-7.219kJ) / (0.1625mol) = -44.42 kJ/mol
