Question

For which of the following processes is ΔS_rxn positive?

Select one:

a. 2O_2(g) + 2SO_(g) → 2SO_{3 (g)}

b. Crystallization of 1 mole of KNO₃ from a solution

c. Mixing 5 mL of creamer with 250 mL of coffee

d. Condensation of 1 mole of H₂O_(g)

e. None of the above

Answer 1

when entropy of system increased, ΔS_rxn will be positive

a) 4 moles reactant produce 2 mole product. less number of moles in product side. Hence entropy decreased

b) crystallization is liquid to solid conversion:: entropy decreased

c) mixing of two different species ;; more disordered state ;; hence entropy increased .So this is positive entropy change

d) condensation is gas to liquid conversion :: entropy decreased

option C is the answer