Given:
Enthalpy of dissolution for NaOH = 44 kJ/mol
Mass of NaOH = 12.6 g
Mass of water = 250 g
Initial temperature of water T1 = 23 C
To determine:
The final temperature of water, T2
Explanation:
Molar mass of NaOH = 40 g/mol
# moles of NaOH = 12.6 g/ 40 g.mol-1 = 0.315 moles
Heat released during dissolution of 0.315 moles of NaOH=
= 44 * 0.315 = 13.86 kJ = 13860 J
Heat released by NaOH = heat absorbed by water
13860 = m*c*(T2-T1)
13860 = 250*4.18*(T2-23)
T2 = 36.26 C
Ans: The final temperature of water is 36.3 C