Question

The delta h for the solution process when solid sodium hydroxide dissolves in water is 44 kj/mol. when a 12.6 g sample of naoh dissolves in 250 g of water in a coffee cup calorimeter, the temperature increases from 23 degrees celsius to _______. assume that the solution has the same specific heat as liquid water

Answer 1

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