Calculate the mass of ascorbic acid (molecular mass ) that should be dissolved in of acetic acid to…

Calculate the mass of ascorbic acid (molecular mass $= 176\text{ g/mol}$) that should be dissolved in $155\text{ g}$ of acetic acid to cause a depression of freezing point by $1\cdot15\text{ K}$. Assume that ascorbic acid does not dissociate or associate in the solution. ($K_f$ for acetic acid $= 3\cdot9\text{ K kg/mol}$)