Why water expands on freezing?

Answer 1

Water has very high dipole moment at 1.85 debye, due to electronegativity difference between H and O atoms. Thus conferring electrostatic attractions that cause a strong tendency for the molecule to form hydrogen bonds at all times, where each hydrogen atom is in line between two 2 oxygen atoms. Electrostatic attractions between the strong dipole moment of water tend to orient them. In ice, they form tetrahedral arrangements.

This bonding tends to get stronger as the temperature decreases.

When the ice structure is completely bonded the crystalline structure becomes 'open' therefore causing water to expand upon freezing. This hydrogen bonding tendency gets stronger as the temperature gets lower (because there is less thermal energy to shake the hydrogen bonds out of position) and in liquid form, hydrogen bonding still exist until water turns into gaseous state.

Answer 2

liquid expands when frozen because the water molecules are moving slower. Think of a person in the summer, they move about freely but when it is cold they tend to slow down. When water molecules slow down they arrange themselves into a highly organized hexagonal structure that leave spaces in between them, thus causing them structure as a whole to take up more space.

Answer 3

Molecular Geometry and Polarity

Water expands when it freezes due to molecular geometry and the fact that it is a very polar molecule. The water molecule is shaped like an upside-down "v". Due to this shape, when water freezes it make a hexagonal shape such that the slightly negatively charge oxygen atoms are aligned with the slightly positively charge hydrogen atoms -- this is the most stable configuration. (Less polar molecules do not configure themselves in this way because there is less of a reduction in energy if the molecule is not as polar) This orientation leaves space in the middle of the frozen water molecules. That is why water expands when it freezes.

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A+

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Answer 4

because it fills a new space for instance if you put a glass of water in the freezer and then 5 hours later take it out... it will be frozen because its taking the shape of the glass i dont know if this is the write answer im sorry if it is not

Answer 5

Water expands when it is frozen because air gets inside of the water and pushes the liquid outwards

i think.

Answer 6

This is becuase it becomes a solid and the particles expand to fit neatly into a solid square.

Answer 7

because the structure of ice contains spaces between them due to weak hydrogen bonds

Answer 8

Water expands on freezing because the structure of the molecules, H2O, take up more space when aligning in electrochemically crystalline form.

Answer 9

Water expands when frozen because when freezing water, the molecules form a lattice that has more empty space compared to liquid water.