The following processes occur in an internal combustion engine. For which one is the entropy change negative?
Compression of the gasoline/air mixture in a piston
Ignition: 2 C8H18 (octane) (g) + 25 O2 (g) --> 16 CO2 (g) + 18 H2O (g)
Expansion of hot CO2 (g) and H2O (g) in a piston
Release of CO2 (g) and H2O (g) into the air
All of these have a positive entropy change.