A vertical piston-cylinder device contains water and is

Problem 40P

A vertical piston-cylinder device contains water and is being heated on top of a range. During the process, 65 Btu of heat is transferred to the water, and heat losses from the side walls amount to 8 Btu. The piston rises as a result of evaporation, and 5 Btu of work is done by the vapor. Determine the change in the energy of the water for this process.

                                                               Step by step solution

Step 1 of 2

Calculate the change in the energy of the water in the cylinder by applying energy balance on this closed system.

Here, heat energy transfer into the system is  , output work done by the system is , heat energy transfer to out of the system is , change in internal energy is , input internal energy is , and output internal energy is