Density measure the amount of mass in a given volume of substance or how much material is in a given space. The density is constant for a substance at a given temperature since increasing the mass of a sample will increase the volume at a proportional rate. Density is calculated by dividing the mass of a substance by the volume (density = mass/volume). If the density of a substance is known, determining the mass of a sample will allow the volume to be calculated.
Determine the density of the substance. Many reference sources are available that give the density of different compounds. Commonly used references include the Merck Index and the CRC Handbook of Chemistry and Physics.
Determine the mass of the substance using a balance. Either a triple-beam balance or electronic balance may be used. One method of measuring the mass is to zero the balance with the container for the sample on the balance. Then add the sample to the container and measure the mass of the container and sample. Alternatively, the mass may be determined by measuring the mass of the container and then the mass of the container with the substance. Subtract the mass of the container from the mass of the substance and container to calculate the mass of the substance (mass of substance = mass of container and substance – mass of container).
Calculate the volume of the substance by dividing the mass of the substance by the density (volume = mass/density). Ensure the units are kept constant during the calculations. Pay attention to the units of measure to ensure an appropriate result. For example, if the density is given in kg per L and the mass was measured in g, convert the g to kg to produce a volume in L.