Density is the weight relation to the volume occupied by her – for solid bodies, and the relation of molar weight to molar volume – for gases. In the most general view the volume (or molar volume) will be the weight relation (or molar weight) to its density. Density is known. What should I do? At first to determine weight, then to calculate volume, then to make necessary amendments.
Instruction
1. The volume of gas is equal to the relation of the work of amount of the substance increased by its molar weight – to already known density. In other words, even knowing density, it is necessary to know the molar mass of gas and amount of substance, that is – how many you have a mol of gas. In principle, knowing how many mol of gas you have, it is possible to calculate its volume, even without knowing density – according to Avogadro's law, one mol of any gas occupies the volume of 22.4 l. If it is obligatory to calculate volume through density, then you need to learn the mass of gas in the unknown volume so far.
2. The volume of a solid body can be determined, even without knowing density, having just measured it, and in case of difficult and very irregular shape the volume is determined, for example, by the volume of the liquid which is forced out by a solid body. However, if it is necessary to calculate volume through density, then the volume of a solid body is the body weight relation to its density, and weight usually is defined by simple weighing. If it is impossible to weigh a body for some reason (for example, it too big or moves), then it is necessary to resort to quite difficult indirect calculations. For example, for a moving body weight is the relation of the doubled kinetic energy to a square of its speed, or the relation of force applied to a body to its acceleration. For very big based body it is necessary to resort to calculations in relation to the mass of Earth, with use of a gravitational constant and the moment of rotation. Or – through calculation of specific heat of substance; anyway knowledge there will only be not enough density for calculation of volume.
3. Having calculated the mass of a solid body, it is possible to calculate volume – simple division of weight into density.