So, what you are probably re â¦ ferring to is 'energy'. The SI unit of energy is the joule (J). An alternative unit, used by electricity utility companies for the purpose of billing its consumers, is the kilowatt hour (kW.h).
a typical steel 30 pound liquid propane tank weighs about 25-28 pounds empty. propane tank markings (on collar) propane weighs about 4.125 pounds per gallon and a 30 po â¦ und tank will hold about 7.5 gallons so a full tank will weigh about 55 pounds or so. /source: wiki.answers.com/.
When you want to know how much gas is left in tank, weigh the tank and compare the numbers. 4. Propane weighs 4.24 pounds per gallon. Each pound contains about 21,500 BTUs which translates to 91,500 BTUs per gallon. A standard '20 pound' tank will be filled to about 17 pounds or a little more. Thus, a 'full' tank contains roughly 365,000 BTUs of energy.