Oxygen in liquid form can be separated from air by Chromatography
Simple distillation
Fractional distillation
Centrifugation

Explanation:

Fractional distillation uses the different boiling points of the main elements of air. As the liquid air is heated, the elements change from liquid to gas and separate from one another. At this point, the carbon dioxide will become solid and drop from the cooled air, leaving nitrogen, oxygen and argon in the air.

5.6⋅10−^19  j

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