Q22 of 22 Page 182

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

It is given that an energy of 286 kJ is released per mole, when water is formed under standard conditions. This means 286 kJ of energy is absorbed by the surroundings in this process. So,

q = - ∆H = 286 kJ mol-1


∆S = q/T


⇒ ∆S = 286 kJ/ 298 K


⇒ ∆S = 959.73 J mol-1K-1


T = Temperature = 298K


More from this chapter

All 22 →
18

For the reaction,

2 Cl(g) → Cl2(g), what are the signs of and ?

 19

For the reaction

2 A(g) + B(g) → 2D(g)


= –10.5 kJ and = –44.1 JK–1.


Calculate for the reaction, and predict whether the reaction may occur spontaneously.

 20

The equilibrium constant for a reaction is 10. What will be the value of ? R = 8.314 JK–1 mol–1, T = 300 K.

 21

Comment on the thermodynamic stability of NO(g), given

N2(g) +O2(g) → NO(g); = 90 kJ mol–1


NO(g) +O2(g) → NO2(g): = –74 kJ mol–1