One gallon of water weighs how many pounds?

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Multiple Choice

One gallon of water weighs how many pounds?

Water weight per volume is determined by density times volume. For U.S. units, one gallon is 3.785 liters, and water at common temperatures has a density close to 1 kilogram per liter. So 3.785 liters of water weigh about 3.785 kilograms, which is roughly 8.345 pounds. That’s why the standard figure used is about 8.34 pounds per gallon. A helpful cross-check: a cubic foot of water weighs about 62.4 pounds, and there are about 7.48 gallons in a cubic foot. Dividing 62.4 by 7.48 gives roughly 8.35 pounds per gallon, aligning with the 8.34 pounds value. The other numbers reflect different quantities (for example, a cubic foot’s weight or the gallons-per-cubic-foot conversion) rather than the weight per gallon.

Water weight per volume is determined by density times volume. For U.S. units, one gallon is 3.785 liters, and water at common temperatures has a density close to 1 kilogram per liter. So 3.785 liters of water weigh about 3.785 kilograms, which is roughly 8.345 pounds. That’s why the standard figure used is about 8.34 pounds per gallon.

A helpful cross-check: a cubic foot of water weighs about 62.4 pounds, and there are about 7.48 gallons in a cubic foot. Dividing 62.4 by 7.48 gives roughly 8.35 pounds per gallon, aligning with the 8.34 pounds value.

The other numbers reflect different quantities (for example, a cubic foot’s weight or the gallons-per-cubic-foot conversion) rather than the weight per gallon.

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