Irreversible versus Reversible Processes

Part A

Which of the following conditions should be met to make aprocess perfectly reversible?

Check all that apply.

(1)correct	Any mechanical interactions taking place in the process shouldbe frictionless.
(2)correct	correct)Any thermal interactions taking place in the processshould occur across infinitesimal temperature or pressuregradients.
(3)	The system should not be close to equilibrium.

Part B

Based on the results found in the previous part, which of thefollowing processes are not reversible?

Check all that apply.

(1)	Melting of ice in an insulated ice-water mixture at 0°C.
(2)	Lowering a frictionless piston in a cylinder by placing a bagof sand on top of the piston.
(3)	Lifting the piston described in the previous statement byremoving one grain of sand at a time.
(4)	Freezing water originally at 5°C.