what is the percent by mass of solution (d =1,3g/ml) of urea ((NH2)2CO) with molarity 8,4mol/l?

% w/w = (grams solute/g solution)*100 = ?.

M = 8.4 mols/L.
mols = grams/molar mass so g = mols x molar mass = 8.4 x 62 = approx 521 g in the solution so g solute = approx 521.
The solution has a mass of 1.3g x 1000 = approx 1300 grams.

Now % = approx 521/1300)*100 = ?

To find the percent by mass of a solution, we need to know the mass of the solute and the mass of the solution.

To calculate the mass of the solute (urea):
To find the mass of urea, we can use the equation:
Mass = Molarity * Volume * Molar mass

The molar mass of urea ((NH2)2CO) is calculated as follows:
1 nitrogen (N) atom weighs approximately 14 grams per mole,
4 hydrogen (H) atoms weigh approximately 1 gram per mole each,
and 1 carbon (C) atom weighs approximately 12 grams per mole,
for a total of 60 grams per mole.

So, to find the mass of urea, we can use the equation:
Mass = Molarity * Volume * Molar mass
Mass = 8.4 mol/L * Volume * 60 g/mol

To calculate the volume of the solution:
Since we know the density of the solution (d = 1.3 g/mL), and density is defined as the mass per unit volume, we can use the equation:
Volume = Mass of solution / Density

Since the molarity is given as 8.4 mol/L, the mass of the solution is equal to:
Mass of solution = 8.4 mol/L * Volume of solution * 60 g/mol

By substituting the equation for the mass of solution into the volume equation, we get:
Volume = (8.4 mol/L * Volume * 60 g/mol) / 1.3 g/mL

Now we can solve for the volume of the solution, which gives us a value in milliliters.

Finally, to find the percent by mass of the solution, we use the formula:
Percent by mass = (mass of solute / mass of solution) * 100

By plugging in the values obtained for the mass of the solute and the mass of the solution, we can calculate the percent by mass of the solution.