I will assume that you are talking about a 42 gallon barrel of pure water at 60 F.
m = ( d ) ( V )
m = ( 8.338 lbm / gal ) ( 42 gal ) = 350.2 lbm <--------------
375.93 lbs
350lbs
That would all depend on the barrels height.
At 17oC one gallon of water weighs 4.536kg.
150 milliliters of pure water weigh 150 grams.
About 0.42 ounces. Specific gravity (compared to water) about 0.73
In general a fluid ounce of water will be an ounce of weight. A pint of water is 16 ounces which would be one pound.
A standard barrel (Drum) is 55 gallons, therefore if the barrel is full of water it would weigh 440 pounds. An oil barrel is smaller and holds only 40 gallons and weigh apx 280 lbs as petroleum is lighter than water
If you filled a British Beer Barrel with water, it would weigh 163kg, or 359lb. If you have a barrel that you want to know the volume of, then we need to know the height, the radius of the widest part, and the raduis of the top. For other barrel sizes, look at en.wikipedia.org/wiki/Barrel_(unit)
One once
100 US gallons of water is about 835 pounds.
2 liters
834.5 pounds.
That would all depend on the barrels height.
At 17oC one gallon of water weighs 4.536kg.
150 milliliters of pure water weigh 150 grams.
One cubic centimeter of water would fit into that cup, and it would weigh 1 gram.
I litre of water weighs one kilogram on year and would weigh 0.1 kilograms.
about 4kg