Calculadora de % Concentração → Molaridade

This calculator converts percentage concentration (mass/mass) of a solution to molarity (mol/L), using the solution density and the solute molar mass. The formula used is M = (% × ρ × 10) / MM, where % is the percentage by mass, ρ is density in g/mL, and MM is molar mass in g/mol. The factor 10 converts density from g/mL to g/L and adjusts the percentage to a decimal fraction.

To use the tool, enter the percentage value (0 to 100), the solution density (in g/mL), and the solute molar mass (in g/mol). Click 'Calculate' to obtain the molarity. The result is rounded to four decimal places. This calculation is essential in chemistry labs for preparing solutions from concentrated reagents, such as acids or bases, whose concentration is often expressed as % m/m.

Practical applications include diluting concentrated sulfuric acid (98% m/m, density 1.84 g/mL) to obtain a known molarity solution, or preparing standard solutions for titrations. Accurate density and molar mass values are critical, as small errors significantly affect the result. The calculator assumes the percentage is mass/mass; for % volume/volume, additional adjustment is needed.

Cautions: check that the density corresponds to the solution temperature, as it varies with temperature. The molar mass should be that of the pure solute, not the solution. For very dilute solutions (%, density approaches that of water (1 g/mL), but using the actual value is still recommended. This tool does not replace laboratory equipment calibration.