How is molarity defined in chemistry?

Molarity is a crucial concept in chemistry defined as the number of moles of solute per liter of solution. This relationship captures the concentration of a solution, indicating how many moles of a given substance are present in a specific volume of the solvent. Therefore, the correct definition of molarity is expressed as moles divided by liters of solution, which addresses how solute concentration affects chemical reactions and solution properties.

The definitions provided in the other options, while related to different aspects of chemistry, do not accurately represent the concept of molarity. For instance, mass/molecular weight would give you the number of moles rather than directly defining concentration. Volume/mass pertains more to density and not concentration. Lastly, mass/volume might suggest a different concentration measure, such as density or mass concentration, rather than molarity.

Understanding molarity plays a pivotal role in quantitative chemistry, helping in calculations involving reaction stoichiometry, solution preparation, and understanding the behavior of solutions in various chemical contexts.