8.8 lbs per gallon
1 Gallon of liquid helium = 11.418 lbs
Liquid nitrogen has a density of 0.807, and one US gallon of water weighs 1 Gallons [US] = 8.345 Pounds. 8.345 Pounds times 0.807 = 6.734 pounds.
How much does 4000 ml weigh in pounds
FYI, One Mole of Oxygen weights 15.9994 grams. AKA Atomic weight of oxygen = 16, Relative atomic mass of oxygen = 16.
I found on a patent website "At -263° F and 1 atmosphere specific gravity of liquid methane is 0.415 , the density is 25.9 lbs. per ft.3, " US gallon is 0.1336806 of a cubic foot thus 3.462 pounds...