Molality is a measure of concentration that relates the moles of solute to the kilograms of solvent, it is described by the following equation:
We are given the molality(2.50m) and kilograms of solvent(0.500kg), so we solve for moles of solute from the equation:
To make a 2.50molal NaOH solution would be needed 1.25moles of solute
Answer: 1.25 moles
Answer:
- The molar mass of the solute, in order to convert from moles of solute to grams of solute.
- The density of solution, to convert from volume of solution to mass of solution.
Explanation:
Hello,
In this case, since molarity is mathematically defined as the moles of solute divided by the volume of solution and the weight/weight percent as the mass of solute divided by the mass of solution, we need:
- The molar mass of the solute, in order to convert from moles of solute to grams of solute.
- The density of solution, to convert from volume of solution to mass of solution.
For instance, if a 1-M solution of HCl has a density of 1.125 g/mL, we can compute the w/w% as follows:
Whereas the first factor corresponds to the molar mass of HCl, the second one the conversion from L to mL of solution and the third one the density to express in terms of grams of solution.
Regards.