Question

Explain an activity to find out the concentration of a solution.

Answer 1

Objective: To find out the concentration of a solution.

Materials/Apparatus required: sugar$\left({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\right)$, salt$\left(\mathrm{NaCl}\right)$, beakers, stirring rod, bunsen burner.

Procedure:

1. Take approximately $50\mathrm{g}$ water in a beaker.
2. Stir continuously while adding $10\mathrm{g}$salt to the beaker.
3. Once the solute can no longer be dissolved, raise the temperature of the beaker by about $5°\mathrm{c}$.
4. Continue adding the solute.
5. Observe and record your findings.

Observation:

1. When there is no more solute that can be dissolved in a solution at a given temperature, it is called a saturated solution.
2. At a given temperature, amounts of salt that can be dissolved in water are different.
3. Consequently, at any given temperature, a solution that has dissolved all the solute that it is not capable of dissolving more is referred to as a saturated solution.

Calculation:

Taken,

$\mathrm{Solute}\left(\mathrm{salt}\right)=10\mathrm{g}$

$\mathrm{Solvent}=50\mathrm{g}$

as we know,

$\mathrm{Solution}=\mathrm{mass}\mathrm{of}\mathrm{solute}+\mathrm{mass}\mathrm{of}\mathrm{solvent}$

$\mathrm{solution}=50+10=60\mathrm{g}$

$\mathrm{Concentration}\mathrm{of}\mathrm{solution}=\mathrm{amount}\mathrm{of}\mathrm{solute}/\mathrm{amount}\mathrm{of}\mathrm{solution}$

$$\begin{gathered} \mathrm{Concentration}\mathrm{of}\mathrm{solution}=10/60 \\ =1.666\mathrm{g} \end{gathered}$$

Therefore, the concentration of solution =$1.66\mathrm{g}$ weight by weight.

The result of this activity demonstrates that different substances dissolve differently in a given solvent at the same temperature.