Скачать или смотреть Difference in Boiling Points for H2O and H2S

In this video we compare the boiling points of Hydrogen sulfide (H2S) and Water (H2O)based on their intermolecular forces. Intermolecular forces (e.g. dipole-dipole and London Forces) can tells us how much the molecules are attracted to each other. The more attraction, the more energy required to make the liquid boil, and therefor the higher the boiling point.

H2O is a polar molecule and there are dipole-dipole intermolecular forces. H2S is also polar and has dipole-dipole interactions. However, since H2O has a greater difference in electronegativities between atoms it will be more polar. This leads to a greater attraction between H2O molecules. Therefore H2O has a higher boiling point than H2S.

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Note that for the boiling points we are talking about Standard Pressure or 1 atm. Changing the pressure will also lead to changes in the boiling point.