Approximately how much helium gas will be produced in a 2000-liter cryostat that is 90% full?

To determine the amount of helium gas that will be produced in a 2000-liter cryostat that is 90% full, we first calculate the volume of helium present in the cryostat.

When the cryostat is 90% full, it contains approximately 1800 liters of liquid helium (since 90% of 2000 liters is 1800 liters). Upon evaporating, liquid helium turns into gas, and the expansion ratio for liquid helium to gas at standard atmospheric pressure is around 757:1. This means that 1 liter of liquid helium will produce approximately 757 liters of helium gas when it completely vaporizes.

Using this ratio, if we take 1800 liters of liquid helium and apply the expansion ratio, we would calculate:

1800 liters (liquid helium) × 757 liters (gas per liter of liquid) = 1,366,600 liters of helium gas.

However, the question asks for an approximate figure, typically rounding to the nearest significant number. The closest rounded estimate to 1,366,600 liters is indeed 1,000,000 liters when considering negligence in significant figures for practical purposes.

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