Question

A vertical piston–cylinder device contains water and is being heated on top of a range. During the process, 73 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.

Answer 1

60 btu

Step-by-step explanation:

given:

`E_(h) =73 btu\\E_(loss) =8 btu\\\\W_(p) =5btu\\`

solution:

the total change in the system energy can be calculated as follows

ΔE=
`E_(h) -W_(p) -E_(loss)`

=73-5-8

=60 btu

note :

work is done by the system so it has a negative sign