Sucrose yet so far.

Hydrogen bonding. Polar molecules. Mutual attraction. And why so much sugar can dissolve in our drinks.

 

a lot of sucrose can dissolve in water in large part because of hydrogen bonding1-Minute NomNom

“You are so full of it but I can’t help being attracted to you!”

That is what sugar molecules might say to water molecules because a lot of sucrose (i.e. table sugar) can dissolve in water (or any of our favorite drinks like coffee or tea).

Table sugar i.e. sucroseTo get a sense of how much sucrose can dissolve in water, we need look no further than the sugar in soda drinks, which are made up mostly of carbonated water and sugar.

A can of soda has about 40 grams of sugar.  That is about 10 teaspoons of sucrose. Imagine spooning that amount of sugar in one meal (and we bet you have have not ever done that before!). That is a lot!

How can so much sucrose dissolve in water?  It all has to do with molecular structure, polar molecules, hydrogen bonding, and mutual attraction.


Molecular structure…

sucrose molecules have a somewhat open latticeworkThe distance between water molecules is about 0.30 nanometer. It might seem they are so close to each other but yet they are fairly far apart. When we look at its molecular structure…

“… at the submicroscipic level, water isn’t a densely packed pile of molecules. It’s a somewhat open latticework, with the molecules connected to one another in tangled strings. The holes in this latticework can accommodate a surprising number of dissolved particles.” (Source: What Einstein Told His Cook)

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… and Hydrogen Bonding, Polar Molecules and Mutual Attractionhydrogen bondingAt the same time, in a water molecule (see above), hydrogen atoms are partially positively charged (∂+) while the oxygen atoms are partially negatively charged (∂-).

hydrogen bonding occurs between the polar sucrose molecules and polar water molecules

Coincidentally, the sucrose molecules also have O-H bonds, where there is a partially positive charged hydrogen atom and a partially negatively charged oxygen atom (see above).hydrogen bondingThis means both water and sucrose are polar molecules, where different ends of the molecules have different charges. As a result, the positively and negatively charged areas on sucrose will attract the negatively and positively charged areas on water respectively, and vice-versa (see the black dots/lines above). These are strong enough to pull sucrose molecules away from the attraction they have for each other.

It is thus this mutual attraction, also known as hydrogen bonding between the polar sucrose molecules and polar water molecules, and the “holes” in water’s structure that makes it possible for so much sugar to dissolve in water.

sucrose dissolves readily in water partly because of hydrogen bonding

 

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photos: in order – depositphotos/Yotkacopridsciencepicslogos2012bernjuerlogos2012stock@photographyfirm.co.uk

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