A bioactive compound, Eupatorin $($Eu$)$ is extracted from the leaves of Misai Kucing, a Malaysia herb through an extraction process using solvent $($S$).$ About $1000kg$ of leaves is required to produce $1kg$ of Eupatorin $($if $100\%$ extraction is achieved$).$ The solvent is a mixture containing $17wt\%$ ethanol $($E$)$ and the balance water $($W$).$ The extraction tank is charged with $3500kg$ of S and $750kg$ of Misai Kucing leaves. The contents are stirred for several hours during which a portion of the bioactive compound contained in the leaves goes into the solution.

The contents of the extraction tank are then discharged through a filter. The liquid filtrate, which carries over roughly $1\%$ of the leaves fed to the extraction tank, is pumped to a holding tank. The solid cake contains spent leaves and entrained liquid. The entrained liquid has the same composition as the liquid solution in the filtrate and a mass equal to $15\%$ of the mass of liquid charged to the extraction tank.

$($a$)$ Redraw the flowchart above and label it completely. Also draw all possible boundaries that can be used to solve the mass balance problem.

$($b$)$ Perform the degree of freedom analysis for the overall process, extraction tank and filter.

$($c$)$ Calculate the masses $($in $kg)$ of the components of the filtrate in the holding tank.

$($d$)$ Calculate the mass of Eupatorin in the solid cake which can be further extracted.