Question

A gas has weight of 5 pounds and a volume of 100 cubic feet. what's the specific volume of this gas

Answer 1

In thermodynamics, specific volume is considered to be an intrinsic property of matter. What we meant by intrinsic property is that, the value of this property does not change no matter the size of the sample. This is opposite to weight or volume which changes depending on the size of the sample.

By mathematical definition, specific volume is the ratio of the substance’s volume to its mass. Or in other words, this is the reciprocal of density.

The formula for density is:

density = mass / volume

Since specific volume is reciprocal so:

Specific volume = 1 / density = volume / mass

 

Calculating:

Specific volume = 100 ft^3 / 5 pounds

Specific volume = 20 ft^3 / pound

 

Or when asked in units of m^3 / kg, we convert:

Specific volume = (20 ft^3 / pound) (2.2 pound / kg) (1 m^3 / 35.3147 ft^3)

Specific volume = 1.246 m^3 / kg