Step-by-step explanation:
The dissolution reaction of NaOH is:
NaOH (s) -----> Na⁺ (aq) + OH⁻ (aq) + 44.5 kJ/mol
ΔH(soln) = –44.5 kJ/mol
This reaction is exothermic, because the ΔH is negative. That's why the 44.5 kJ/mol appears in the products side, because heat is being released.
From the ΔH of solution we know that 1 mol of NaOH will realease 44.5 kJ when it dissolves. We have to find the heat released by 0.677 mol of NaOH.
Heat released = 0.677 moles * (-44.5 kJ/mol)
Heat released = - 30.1 kJ
Answer: -30.1 kJ is released when 0.677 mol of NaOH is dissolved.