For each process of a closed system, show the initial and final states on a properly-labeled T-s diagram, evaluate the change in entropy, and apply the entropy balance and energy balances, as necessary, to answer the specific questions. In each case, neglect changes in kinetic and potential energy.
1. R-134a is compressed adiabatically from saturated vapor at 8C to 10 bar, 50C. Is this process possible? Determine the work, in kJ per kg of R-134a. What is the minimum work input possible for adiabatic compression from the same initial state to a final pressure of 10 bar?
2. One lb of water is contained in a 40-ft^2 tank, initially at 10 lbf/in^2 An electrical resistance element transfers energy by work of W = - 300 Btu until the final pressure is 20 lbf/in^2 Determine the energy transfer by heat, in Btu. Is the process possible? Reversible?