In chemistry, m=cv is a law of mass conservation derived from the conservation of matter, which means that the change of system mass is always equal to the difference between the input and output mass of the system. The law of conservation of mass is one of the basic laws prevailing in nature. Explain that quality will neither be created nor destroyed, but will only be transferred from one substance to another, and the total amount will remain unchanged. M stands for the mass of the substance, and the unit is g, and c stands for the solution. The name of concentration is mass concentration, and the unit is g/ml. V is the volume of the solution in milliliters. M=cv, that is, m = g in m=ml. ml=g .

Should be N=cv. M is mass. C is the concentration of substance (mol in l), V is the volume (L), and the product should be mol, instead of g.mv. M can be regarded as m divided by m and then divided by v. M divided by m is the number of moles of substance, and n divided by v is the number of moles per unit volume, which is the mass concentration of substance.

The volume in the substance concentration formula refers to the volume of the solution, not the volume of the solvent. Take out any volume of solution from a solution containing a certain amount and concentration of substances, the concentration of which remains unchanged, but the quantity or quality of solute substances contained varies with the volume.