In thermodynamics, mass is defined as the measure of the amount of substance present in a system. It is a fundamental property of matter and is usually measured in kilograms (kg) or grams (g).
The mass of helium present in a system can be determined by measuring the total mass of the system and subtracting the mass of all other components present. Alternatively, it can also be calculated by knowing the molar mass of helium and the number of moles present in the system.
In thermodynamics, the mass of a closed system remains constant, meaning it cannot be created or destroyed. Therefore, the mass of helium present in a closed system will remain the same unless there is a transfer of mass into or out of the system.
Temperature has a direct effect on the mass of helium present in a system. As the temperature increases, the average kinetic energy of the helium particles also increases, causing them to move faster and take up more space. This results in a decrease in density and therefore a decrease in mass for a given volume of helium.
According to the Ideal Gas Law, the mass of a gas is directly proportional to its pressure and volume. Therefore, an increase in pressure will result in an increase in the mass of helium present in a system, while a decrease in pressure will lead to a decrease in mass.