Question

How can the amount of solute in a solution be calculated?

Answer 1

Hint: Solution is a mixture of more than one pure substance. A dilute aqueous solution of sugar revives the size of partially dried resins while a concentrate aqueous solution of sugar decreases the size of fresh resins by dehydration. Dysentery and dehydration is treated by aqueous solution of salts.

Complete answer:
It may be noted that molality, mole fraction and mass fraction are preferred to molarity, normality etc, because the former involves mass of solute and solvents whereas the later involves volume of solution. Temperature has no effect on mass but has a significant effect on volume.

Mass percentage : the mass percentage of a solution is defined as $$={\displaystyle \frac{\text{ mass of components}}{\text{mass of all the components of solution}}}\times 100$$
Mass$\mathrm{\%}$ of a component = mass of the component in the solution upon total volume of solution.
But percentage: this can be defined as: $$({\displaystyle \frac{v}{v}})\mathrm{\%}={\displaystyle \frac{\text{volume of components}}{\text{volume of all the components of solution}}}\times 100$$
Volume$\mathrm{\%}$ of a component= volume of the given component per total volume of solution ×100
Mass of volume percentage =weight of solute per volume of solution (100ml) $$({\displaystyle \frac{m}{v}})\mathrm{\%}={\displaystyle \frac{\text{mass of solute }}{\text{volume of solution(100ml)}}}$$
Mole fraction ($$\chi$$):
Mole fraction of a component: number of moles of the component /total number of moles of all the components $$={\displaystyle \frac{\text{number of moles of components}}{\text{number of moles of all the components}}}$$
In a binary solution having a number of moles as $N_a$ and $N_b$.
Molality (m): it is defined as the number of moles of solute dissolved per kg of the solvent.
 Molality: $${\displaystyle \frac{\text{number of moles of solute}}{\text{mass of solvents in kg}}}\times 100$$

Note:
 It may be noted that molality, mole fraction and mass fraction are preferred to molarity, normality etc, because the former involves mass of solute and solvents whereas the latter involves volume of solution. Temperature has no effect on mass but has a significant effect on volume.