What is Mass % of an aqueous NaOH solution in which molality of NaOH is 16.7m? Density of the solution is 1.4339g/ml
16.7 m means 16.7 mol NaOH/kg solvent.
16.7 mol NaOH = mols x molar mass = about 670 g but you need to this more accurately.
Thus 16.7 m contains about 670g NaOH/kg solvent. That is 670g/1000 g solvent.
The solution, then, must weigh 1000g + 670 g = 1670g.
mass% = (670/1670)*100 = ?
You don't need the density to calculate mass%.
To determine the mass percent of an aqueous NaOH solution, we need to know the mass of NaOH and the total mass of the solution.
To find the mass of NaOH, we can use its molality and the mass of the solvent (water). The formula for molality (b) is:
molality (b) = moles of solute / mass of solvent (in kg)
We are given the molality of NaOH as 16.7 m, so we can rearrange the formula to solve for the moles of NaOH:
moles of NaOH = molality (b) x mass of solvent (in kg)
Next, we need to convert the mass of solvent (in kg) to grams. The density of the solution is given as 1.4339 g/ml, which means that 1 ml of the solution has a mass of 1.4339 g. We can use this information to find the volume of the solvent (water) in ml.
mass of solvent (in g) = mass of solvent (in ml) x density
Since we have the density and the mass of the solvent (in g), we can rearrange the formula to solve for the volume of the solvent:
volume of solvent (in ml) = mass of solvent (in g) / density
Finally, we need to convert the volume of the solvent (in ml) to kg:
mass of solvent (in kg) = volume of solvent (in ml) / 1000
Now that we have the moles of NaOH and the mass of the solvent (in kg), we can calculate the mass percent of NaOH in the solution using the following formula:
mass percent = (mass of NaOH / total mass of solution) x 100
To get the total mass of the solution, we need to add the mass of NaOH to the mass of the solvent.
I hope this explanation helps you understand how to solve the problem. If you have any further questions, please let me know.