Not sure how this can get, but how is that two atoms of hydrogen and one atom of oxygen combine into something (water) that’s heavier than air even though they’re lighter than air separately?

Question

Not sure how this can get, but how is that two atoms of hydrogen and one atom of oxygen combine into something (water) that’s heavier than air even though they’re lighter than air separately?

In: Chemistry

Answer 1

Water quite close in density to air if they are in the same state(liquid, solid or gas). So if you have both the air and water as gas the density of water is less

Att 100C the density of air is 0.947 kg/m3 compared to 0.6 kg/m3 for water
An H2O molecule has the mass of 18U and the air is primary N2 at 28U and O2 at 32U

As a liquid O2 have a density of 1.141 g/cm3 but need to be at at -182. Liquid N2 has a density of 0.808 g/cm3 and needs to be at -195.79C. Water has a density of 1g/cm3 so oxygen is a bit denser but nitrogen is less dense.

If you include liquid hydrogen the density is only 0.07085g/cm3 and it needs to be −252.87 °C

The difference is not density but boiling temperature. It is because of the strong hydrogen bonds between the H2O molecules where the 3D shape of it has a huge effect.