$2.-$ As a process engineer, you decide to develop a first$-$order model with downtime of your process by making a step change in the process. The process is initially at steady state, with a feed of $5$gpm and an output of $0\mathrm{.}75$ mol$/$L$.$ You make a $0\mathrm{.}5$gpm increase in feeding at$3$:$00$ pm but you don't see any change in the output before $3$:$07$ pm$.$ At $3$:$20$ PM the output is $0\mathrm{.}8$ mol$/$L$.$ You get distracted by some reports that were requested of you, so you don't check the process again until $6$:$30$ PM$,$ when you are ready to leave for home. At that point you see that the output has stabilized at $0\mathrm{.}85$mol$/$L What are the parameters of the system $($with units$)?$