MHB Why is Water Less Dense than Ethanol?

[markosheehan]

Why is ethanol less dense than water if ethanol has a larger molecular weight. I think i heard it's something to do with water molecules being closer to each other. Why is this?

 

[I like Serena]

Why is ethanol less dense than water if ethanol has a larger molecular weight. I think i heard it's something to do with water molecules being closer to each other. Why is this?

Water has a polar molecular structure.
That is, the H-O-H atoms make an angle, causing a so called dipole moment, being negatively charged on one end, and positively charged on the other end.
Consequently $H_2O$ molecules have a stronger attraction to each other, and also to other polar molecules.

 

[markosheehan]

Water has a polar molecular structure.
That is, the H-O-H atoms make an angle, causing a so called dipole moment, being negatively charged on one end, and positively charged on the other end.
Consequently $H_2O$ molecules have a stronger attraction to each other, and also to other polar molecules.

Thanks