### Video Transcript

A 0.80-liter solution contains 0.40 moles of acetic acid. What is the molar concentration of acetic acid in this solution?

This question is asking us to calculate the molar concentration of acetic acid in a solution. Molar concentration, also known as molarity, is defined as the number of moles of solute per liter of solution. In this problem, acetic acid is the solute that is dissolved in the solution. To calculate the molar concentration of acetic acid in the solution, we’ll need to make use of the molarity equation. In this equation, 𝑐 is the molar concentration in moles per liter, 𝑛 is the amount of solute in moles, and 𝑣 is the volume of the solution in liters. We know that to solve this problem, we must determine the molar concentration, or 𝑐.

Let’s identify the measurements that are given in the problem. The volume of the solution given in the problem is 0.80 liters. And the amount of solute in moles is 0.40 moles. Now, we’re ready to substitute the amount of acetic acid in moles and the volume of the solution in liters into the molarity equation. We can write 𝑐 equals 0.40 moles divided by 0.80 liters. After dividing 0.40 moles by 0.80 liters, we get an answer of 0.5 moles per liter. The units moles per liter are just one way to represent the molar concentration of a solution.

Chemists also use a capital M to represent the molarity of a solution. When reading the molar concentration expressed with capital M, the word molar is used. The molar concentration of acetic acid in the solution in this problem is written as 0.5 capital M. And we would read this as a 0.5 molar solution of acetic acid.