Calculate the mass of urea required in making 2.5 kg of 0.25 molal aqueous solution

Chemistry
1

calculate the mass of urea required in making 2.5 kg of 0.25 molal aqueous solution

2

calculate the mass of urea required in making 2.5 kg of 0.25 molal aqueous solution.

Answer:
To calculate the mass of urea required to make a 0.25 molal solution of urea, we need to first understand what molality is.

Molality (m) is defined as the number of moles of solute per kilogram of solvent. So, a 0.25 molal solution contains 0.25 moles of solute (urea) per kilogram of solvent (water).

Given that we want to make a 0.25 molal solution using 2.5 kg of solvent (water), we can calculate the amount of urea required as follows:

  1. First, we need to calculate the mass of water in kilograms:

Mass of water = 2.5 kg

  1. We know the molality of the solution is 0.25 mol/kg. Therefore, we can calculate the number of moles of urea required using the following formula:

Moles of urea = Molality x Mass of solvent (in kg)

Moles of urea = 0.25 mol/kg x 2.5 kg = 0.625 moles

  1. Finally, we can calculate the mass of urea required using its molar mass, which is 60.06 g/mol:

Mass of urea = Moles of urea x Molar mass of urea

Mass of urea = 0.625 moles x 60.06 g/mol = 37.54 g

Therefore, to make a 0.25 molal aqueous solution using 2.5 kg of water, we need 37.54 g of urea.