What is the equation used to calculate concentration in mol/dm³?

The correct answer defines concentration in terms of the number of moles of solute and the volume of the solvent. Concentration is a measure of how much solute is present in a given volume of solution, typically expressed in moles per cubic decimeter (mol/dm³).

In this context, the term "solute" refers to the substance that is dissolved (for example, salt in water), while "solvent" refers to the medium in which the solute is dissolved (in this case, typically water). The equation indicates that the concentration increases as either the number of moles of solute increases or when the volume of the solvent decreases, as both factors directly affect how concentrated the solution will be.

Understanding this relationship is crucial for various applications in chemistry, such as preparing solutions of desired concentrations for experiments or reactions. The other provided options do not accurately represent the correct relationship for determining concentration in the context of chemistry.