Explanation:
Given: <u>Molarity = 0.01 M</u>
Let the volume of the solution = 1 L
Hence, moles = 0.01 moles (Molarity*Volume)
Molar mass of urea = 60 g/mol
So, mass of urea = moles x molar mass = 0.01 moles x 60 g/mol = 0.6 g = 0.0006 kg ,
Given: Density of solvent = Density of solution = 1 Kg/liter (Water).
So,
The mass of solution = vol x density = 1 L x 1 kg/L= 1 kg
Also,
Mass of solution = Mass of solute + Mass of solvent
1 kg= 0.0006 kg + mass of solvent
Mass of solvent = 1-0.0006 = 0.9994 kg
Molality is the moles of solute present in 1 kg of the solvent. So,
<u>Molaity = ( 0.01/0.9994) ≈ 0.01 m</u>
<u>Molarity = Molality</u>
Hence proved.
