How to Measure the Mass of a Liquid & Gas

Mass of a Liquid

• 1

  Determine the density of the liquid by referencing a scientific table of densities or by weighing a known volume of the liquid.

• 2

  Multiply the volume of liquid present by its density.

• 3

  Simplify and cancel all units labels appearing in the numerator and denominator of the equation. Specifically, the unit of liters will cancel out. The resulting value is the mass of the liquid.

Mass of a Gas

• 4

  Multiply the pressure of the gas, in atmospheres, by the volume it occupies.

• 5

  Divide the result by the product of the gas constant and the temperature in Kelvin. For reference, the gas constant is approximately 8.314 joules per mole Kelvin. This operation yields the number of moles of gas present.

• 6

  Multiply the moles of gas present by the molecular weight of the gas. This yields the mass of the material in grams.