Derive the expression of the growth rate for an invariant cubic crystal. Crystals of Epsom salt having equivalent diameter of $1\mathrm{.}5$ cm are growing in a solution of MgSO, at a supersaturation of $0.005-$mole

fraction MgSO,$\mathrm{.}7$H$,0,$ and a temperature of $303$ K$.$ For a saturated solution of MgSO$4,$ the average coefficient of interfacial reaction is $\mathrm{.}18$ gmolcm$^2.$h$.$ mole fraction. The mass transfer coefficient has

been estimated to be $1\mathrm{.}75$ gmol$/$lcm$\text{'}.$A$.$mole fraction. The average density of the crystals is $1\mathrm{.}68$ glcm$\text{'}.$ Assuming the crystals are cubic, calculate their growth rate in cm$/$h$.$