How is molarity defined mathematically?

Molarity is defined mathematically as the number of moles of solute present in one liter of solution. This means that to find the molarity, you take the amount of solute, expressed in moles, and divide it by the volume of the solution, which must be in liters. This relationship illustrates how concentrated a solution is, allowing for comparisons between different solutions.

The other options reflect different measurements related to concentration but don’t capture the essence of molarity. For example, mass of solute divided by the volume of solution does not take into account the number of moles, while expressing concentration in grams per liter is not equivalent to moles per liter, as it relies on the molar mass of the solute for conversion. Lastly, focusing on moles of solute per the volume of the solvent instead of the solution is also an inaccurate representation of how molarity is defined. These distinctions highlight why the correct choice is specifically formulated in terms of moles of solute per liter of the entire solution.