Why does boiled water have less oxygen?

Answer 1

Less oxygen refers to oxygen dissolved in the water rather than oxygen in the water molecules themselves. When the water is boiled the oxygen molecules gain more energy and become more active. This means that they are more likely to reach the surface of the water and escape.

Answer 2

The solubility of gases in water decreases with temperature. If you have a sample of water that has been standing around at room temperature for a while, take half of this and boil it, the boiled half will contain less oxygen (and nitrogen) than the sample that had not just been boiled.
This is because the gases in the air dissolve in the water when it is standing at room temperature. These then boil out of the liquid as the temperature increases and their solubility decreases.
It is important to make a distinction that the Oxygen we're talking about here is molecular oxygen in the air not the oxygen atom that forms each water molecule (H2O).

Answer 3

Because it has evaporated into water vapour. Or do you mean less oxygen than cooler water? Maybe there is enough heat energy to split the oxygen atoms from the hydrogen atoms and they are released, leaving less in the water.

Answer 4

Because much of the oxygen has evaporated from it due to the boiling.

Answer 5

Oxygen lose through evaporating .