Answer:
Molarity is 0.99 M
Explanation:
5.21% by mass, is a sort of concentration which shows the mass of solute in 100 g of solution.
Molarity is a sort of concentration that indicates the moles of solute in 1 L of solution (mol/L)
Let's find out the volume of solution by density.
Solution density = Solution mass / Solution volume
1.15 g/mL = 100 g / Solution volume
Solution volume = 100 g / 1.15 g/mL → 86.9 mL
We must have the volume of solution in L, so let's convert it.
86.9 mL / 1000 = 0.0869 L
Now, we have to determine the moles of solute (urea)
5.21 g . 1 mol / 60 g = 0.0868 moles
Mol/L = Molarity → 0.0868 moles / 0.0869L = 0.99 M
Answer:
[tex]\large \boxed{\text{1.00 mol/L}}[/tex]
Explanation:
Molar concentration = moles/litres
So, we need both the number of moles and the volume.
1. Volume
Assume a volume of 1 L.
That takes care of that.
2. Moles of urea
(a) Mass of solution
[tex]\text{ Mass of solution} = \text{1000 mL} \times \dfrac{\text{1.15 g solution}}{\text{1 mL}} = \text{1150 g solution}[/tex]
(b) Mass of urea
[tex]\text{Mass of urea} = \text{1150 g solution}\times \dfrac{\text{5.21 g urea}}{\text{100 g solution}} = \text{59.92 g urea}[/tex]
(c) Moles of urea
[tex]\text{Moles of urea} = \text{59.92 g urea} \times \dfrac{\text{1 mol urea}}{\text{60.06 g urea}} = \text{1.00 mol urea}[/tex]
3. Molar concentration
[tex]\text{Molar concentration} = \ \dfrac{\text{1.00 mol}}{\text{1 L}} = \textbf{1.00 mol/L}\\\text{The molar concentration of the urea is $\large \boxed{\textbf{1.00 mol/L}}$}[/tex]
