Question

Define molarity.

Short answer

Molarity is a measure of the concentration of a solute in a solution, expressed in moles of solute per liter of solution (mol/L), and denoted by the letter M. The formula for calculating molarity is \(M = \frac{n}{V}\), where \(M\) is the molarity, \(n\) is the number of moles of solute, and \(V\) is the volume of the solution in liters. It is a crucial concept in chemistry for comparing concentrations of different solutions and performing calculations involving chemical reactions.

Step-by-step solution

Definition of Molarity

Molarity is a measure of the concentration of a solute in a solution, expressed as the number of moles of solute per liter of solution (mol/L). It is often denoted by the letter M. This allows us to easily compare the concentrations of different solutions and perform calculations involving chemical reactions.

Formula for Calculating Molarity

The formula for calculating molarity (M) is given by the following equation: \[M = \frac{n}{V}\] where: - \(M\) is the molarity (mol/L) - \(n\) is the number of moles of solute (mol) - \(V\) is the volume of the solution (L)

Understanding Molarity

To better understand molarity, let's consider an example. Suppose we have 1 mole of sodium chloride (NaCl) dissolved in 1 liter of water. The molarity of this sodium chloride solution would be: \[M = \frac{1 \, \text{mol of NaCl}}{1 \, \text{L of solution}}\] Therefore, the molarity of this solution is 1 mol/L, or simply 1 M.

Using Molarity in Calculations

Molarity can be used in various calculations involving chemical reactions. For example, in a titration experiment, the molarity and volume of one reactant can be used to determine the molarity of another reactant: \[M_1V_1 = M_2V_2\] where: - \(M_1\) and \(M_2\) are the molarities of the two reactants - \(V_1\) and \(V_2\) are the volumes of the respective reactants In summary, molarity is a crucial concept in chemistry that helps us define the concentration of a solution and enables us to perform calculations involving chemical reactions.