A 2.30 m solution of urea (CO(NH2)2; FW= 60.0) in water has a density of 1.14 g/mL. Calculate the percent mass of urea in this solution
Answered below.
To calculate the percent mass of urea in the solution, we'll need to determine the mass of urea and the mass of the entire solution.
First, let's calculate the mass of the solution using its density.
Given:
Density of the solution = 1.14 g/mL
Since density = mass/volume, we can rearrange the equation to solve for mass:
mass = density x volume
The volume of the solution is not given explicitly, but we can assume that it refers to 1 liter (1000 mL) for convenience.
mass of solution = 1.14 g/mL x 1000 mL = 1140 g
Now, let's calculate the mass of urea in the solution.
Given:
Concentration of urea = 2.30 molar
Molar mass of urea (FW) = 60.0 g/mol
The molarity (M) of a solution is defined as the number of moles of solute per liter of solution. Since the volume of the solution is 1 liter (1000 mL), the number of moles of urea can be calculated as follows:
moles of urea = concentration x volume
moles of urea = 2.30 mol/L x 1 L = 2.30 mol
To find the mass of urea, we can use the molar mass:
mass of urea = moles of urea x molar mass of urea
mass of urea = 2.30 mol x 60.0 g/mol = 138.0 g
Finally, let's calculate the percent mass of urea in the solution.
percent mass = (mass of urea / mass of solution) x 100
percent mass = (138.0 g / 1140 g) x 100
percent mass ≈ 12.11%
Therefore, the percent mass of urea in this solution is approximately 12.11%.