$1\mathrm{.}19.$ Three $kg$ of saturated liquid water are to be evaporated at $60C.$

a$.$ At what pressure will this occur at equilibrium?

b$.$ What is the initial volume?

c$.$ What is the system volume when $2kg$ have been evaporated? At this point, what is $U_{?}$ relative to the initial state?

d$.$ What are $H_{?}$ and $U_{?}$ relative to the initial state for the process when all three $kg$ have been evaporated?

e$.$ Make a qualitative sketch of parts $($b$)$ through $($d$)$ on a $P-V$ diagram, showing the phase envelope.