For the following reaction, calculate an approximate value for the change in free energy, and determine whether or not the reaction is spontaneous under standard conditions.



Compound
DGf º (kJ/mol)
NO2
52
HCN
125
CO2
–394
H2O
–237
O2
0

–230 kJ/mol, yes
+2300 kJ/mol, yes
–1171 kJ/mol, yes
+230 kJ/mol, no
+2300 kJ/mol, no