chem problem?

Question

what mass of pheno, C6H5OH, (fw=94.11) must be dissolved in 25 g of naphthalene to produce a solution that is 0.22 m in phenol?

Answer 1

You must know the definition of the molality m, do not you? it is the number of moles of the solute in 1kg of solvent.
Now, you asked "0.22 m in phenol", is it 0.22m of naphthalene in phenol, or actually you are asking 0.22m of phenol in naphthalene?
Let us assume that is 0.22 m of naphthalene in phenol. The molar mass of naphthalene is 128.17 g/mol. In 1000g phenol, we need 0.22 x 128.17 = 28.2g of naphthalene. Given 25 g of naphthalene, phenol needs to be reduced to:
(25*1000/28.2)g = 887g.