How do two gases combine to make liquid water?

Asked by: Arthur Newby, Liverpool

Hydrogen and oxygen atoms are attracted to one another by the electrostatic force between their positively charged protons and negatively charged electrons. This chemical bond isn’t very strong – but it’s enough to overcome the random motion that the atoms undergo at temperatures between 0°C and 100°C that would otherwise keep them as separate gases.

As a result, pairs of hydrogen atoms team up with individual oxygen atoms in a relatively dense but loose arrangement of H2O molecules we call liquid water.

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