Chapter 16.2, Problem 19LC

Interpretation Introduction

Interpretation: The molarity of a solution is to be defined and described.

Concept introduction: The concentration of a solution is defined as the amount of solute dissolved or present in the given quantity of solution. Concentration can be expressed in different ways such as molarity, molality, normality, percent by mass, and percent by volume.

Answer to Problem 19LC

To calculate the molarity, divide the number of moles of solute by the volume of the solution. The volume of solution should be in liters.

Explanation of Solution

Molarity is defined as the number of moles of solute present in one liter of the solution. Molarity is also known as molar concentration. The unit of molarity is $\frac{mol}{L}$ which is written as M.

The example to find molarity is as follows:

If 2 mole of $\text{NaCl}$ is dissolved in 2 liters of water, the molarity can be found out as:

  $\text{Molarity = }\frac{\text{number of moles of solute}}{\text{Volume of solution(inL)}}$

  $\begin{array}{l}\text{Molarity = }\frac{\text{2 mole}}{\text{2 L}}\\ \text{Molarity = 1 M}\end{array}$

So, this is how molarity is calculated.

Conclusion

To calculate the molarity, divide the number of moles of solute by the volume of the solution. The volume of solution should be in liters.