Question

Question 6.22 Calculate the entropy change in surroundings when 1.00 mol of H2O(l) is formed under standard conditions. ΔfHθ = –286 kJ mol–1.

Class XI Thermodynamics Page 184

Answer 1

                H2(g) + 1/2O2(g) ---------> H2O (l)
enthalpy change for the formation of water = -286 KJ/mol
  energy released by the formation of water , is absorbed by surroundings . i mean Qs = + 286 KJ/mol 
where Qs is heat of surroundings 
now,
  ΔS = Qs/T
       = 286 KJ/mol/298K [ actually heat of formation finding at room temperature e.g., T = 298K ]
       = 0.9597 KJ/mol/K

Answer 2

Answer:

Explanation:

H2(g) + 1/2O2(g) ---------> H2O (l)

enthalpy change for the formation of water = -286 KJ/mol

  energy released by the formation of water , is absorbed by surroundings . i mean Qs = + 286 KJ/mol 

where Qs is heat of surroundings 

now,

  ΔS = Qs/T

       = 286 KJ/mol/298K [ actually heat of formation finding at room temperature e.g., T = 298K ]

       = 0.9597 KJ/mol/K