Question

What is the concentration of a solution, expressed in g/100 mL, if 25 g of solute dissolved in 40 mL of water?

Answer 1

Hint: Solute is the substance which is added in low quantity. The substance in which the solute is dissolved is called a solvent. The concentration of any solution is a measure of its solute divided by the volume of the solvent or the volume of solution. It is called mass by volume percent when expressed in percentage.

Complete answer:
We have been given the mass of solute as 25 g, which is dissolved in 40 mL of solvent which is water. We have to find the concentration in terms of g/100 mL.
As we know concentration is the expression of the particles of solute dissolved in the solvent or in the total solution. So we will use the formula for concentration as, $concentration=\dfrac{Mass\,of\,solute}{100\,mL\,volume\,of\,solvent}$
We have given the mass of solute = 25 g and volume of solvent = 40 mL, therefore concentration will be,
Concentration = $\dfrac{25\,g}{\left( \dfrac{40}{100} \right)mL}$
Concentration = $\dfrac{25\times 100\,}{40\,}$
Concentration = 62.5 g / 100 mL
Hence, the concentration of 25 g of solute in 40 mL of water is 62.5 g / 100 mL.

Note:
When the volume of solution is taken (in L) with the mass of solute, then the concentration term is called molarity, as it is the number of moles of solute dissolved per liter solution. While the concentration is expressed in molality, when the number of moles of solute is dissolved per kg of the solvent.