Question

Purification of Ni metal can be facilitated by its ability to react with carbon monoxide. Ni(s) + 4CO(g) --> Ni(CO)4(g) Substance: Ni(s) CO(g) Ni(CO)4(g) S°(J/K•mol): 30.1 197.9 410.6 DH° (kJ/mol): 0 -110.5 -602.9 What is DG° for this reaction?

A) –437.9 kJ/K•mol

B) +437.9 kJ/K•mol

C) +38.4 kJ/K•mol

D) –38.4 kJ/K•mol

E) –438.2 kJ/K•mol

Answer 1

Ans: Ni + 4CO -------------------> Ni(CO)4

$\Delta H = H products - H reactants$

= -602.9 - [0+4 (-110.5)

= -160.9 K.J /mol

$\Delta S = S products - S reactants$

= 410.6 - [30.1+4 (197.6)]

= -411.6 J.K^-1/mol^-1

= -0.411 K.J K^-1/mol^-1

$\Delta G = \Delta H - T \Delta S$

In problem Temperature is not mentioned. apply above formula by sustitute temperature in kelvins and caluclate $\Delta G$