Find the mass in grams of aluminum nitrate, Al (NO3) 3, required to mix with 750 g of water to makea 1.5m solution.

Mass = 239.62 g

Explanation:

Molality is given as,

m = Moles of Solute / Kg of Solvent - - - (1)

Data Given;

Molality = 1.5 m

Mass of Solvent = 750 g = 0.75 Kg

Solving eq. 1 for Moles,

Moles = Molality * Mass of Solvent

Putting values,

Moles = 1.5 mol. Kg⁻¹ * 0.75 Kg

Moles = 1.125 mol

Calculating mass from moles,

Moles = Mass / M. mass

Or,

Mass = Moles * M. mass

Putting values,

Mass = 1.125 mol * 213 g. mol⁻¹

Mass = 239.62 g