$13.$ If the efficiency of an extraction process is $85\%$ and the initial amount of solute is $200$ grams, how much solute remains in the feed after extraction?

$14.$ Given a ternary phase diagram where the solubility limit of component A in a mixture is $60\%,$ what is the maximum amount of A that can be dissolved in $100$ g of the mixture?

$15.$ If a supercritical fluid extraction process operates at a pressure of $300$ bar and a temperature of $40$C above the critical point of the solvent, what are the pressure and temperature conditions?

$16.$ A solvent recovery system recaptures $95\%$ of the solvent used in an extraction process. If the process initially used $500$ mL of solvent, how much solvent is recovered?