what mass(g) of NH3 must be dissolved in 475g of methanol to make a 0.25m solution

Answer 1

Is that m as in molal.
m = mols solute/kg solvent
Substitute and solve for mol solute.

Then mols solute = grams solute/molar mass solute. Substitute and solve for grams solute (NH3)

Answer 2

2.02g