What does molarity (M) specifically measure?

Molarity (M) is defined as the concentration of a solute in a solution, specifically measured in moles of solute per liter of solution. This means that when you calculate molarity, you determine how many moles of a given solute are contained within one liter of the entire solution. This measurement is crucial in chemistry because it allows for consistent reactions and dilutions, making it easier to predict how substances will behave when mixed.

In contrast, measuring mass of solute in grams provides no direct information about how concentrated that solute is in relation to the volume of the solvent. Volume in milliliters does not give any insight into the solute's concentration without knowing how much solute is present. Additionally, temperature is a separate property that does not pertain to the measurement of concentration in a solution. Thus, the focus of molarity as a concept is entirely centered around the ratio of moles of solute to volume in liters, making it essential for various calculations in chemistry.