if 7.5g of urea, (NH2)2CO is dissolved in 500g of water (density of resulting solution is 1.25g/mml). what is the molar concentration of the solution?
M = mols/L
mols = g/molar mass = 7.5/60 = 0.125
volume = mass/density = 500/1.25 = 400 mL = 0.400 L
M = 0.125 moles/0.400 L = ?
To determine the molar concentration of the solution, we need to calculate the number of moles of urea and the volume of the resulting solution.
First, let's calculate the number of moles of urea (NH2)2CO.
Molar mass of urea (NH2)2CO = (2*1 + 1*14 + 1*12 + 1*16) g/mol
= 2 + 14 + 12 + 16
= 60 g/mol
Number of moles of urea = mass of urea / molar mass of urea
= 7.5 g / 60 g/mol
= 0.125 mol
Next, let's calculate the volume of the resulting solution.
Density of the solution = 1.25 g/mL
Mass of the solution = mass of water + mass of urea
= 500 g + 7.5 g
= 507.5 g
Volume of the solution = mass of the solution / density of the solution
= 507.5 g / 1.25 g/mL
= 406 mL (or 0.406 L)
Finally, we can calculate the molar concentration:
Molar concentration = number of moles / volume of solution
= 0.125 mol / 0.406 L
≈ 0.3078 mol/L
Therefore, the molar concentration of the solution is approximately 0.3078 mol/L.
To find the molar concentration of the solution, we need to determine the amount of urea (in moles) in the given mass of urea and then divide it by the volume of the solution.
First, let's find the moles of urea in 7.5g of urea.
The molar mass of urea ((NH2)2CO) is:
(2 * molar mass of N) + (4 * molar mass of H) + (1 * molar mass of C) + (1 * molar mass of O)
= (2 * 14.01 g/mol) + (4 * 1.01 g/mol) + (1 * 12.01 g/mol) + (1 * 16.00 g/mol)
= 28.02 g/mol + 4.04 g/mol + 12.01 g/mol + 16.00 g/mol
= 60.07 g/mol
Now, we can calculate the number of moles of urea:
moles of urea = mass of urea / molar mass of urea
= 7.5 g / 60.07 g/mol
Next, we need to find the volume of the solution. We are given the density of the solution, which is 1.25 g/mL. Since the mass of the solution is 500g, we can use the density to find the volume:
volume of solution = mass of solution / density of solution
= 500g / 1.25 g/mL
= 400 mL
Finally, we can calculate the molar concentration:
molar concentration = moles of urea / volume of solution
= (7.5 g / 60.07 g/mol) / 400 mL
To convert mL to L, we divide by 1000:
molar concentration = (7.5 g / 60.07 g/mol) / (400 mL / 1000 mL/L)
= (7.5/60.07) / (400/1000) mol/L
≈ 0.3123 mol/L
Therefore, the molar concentration of the solution is approximately 0.3123 mol/L.