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    Are hydrogen bonds between water molecules actually longer in ice than in liquid water? Do they become longer and hold the h20 molecules apart as water solidifies?

    Thanks
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    The actual structure of liquid water is unknown, but it is thought than the arrangement in ice is a result of the longer hydrogen bonds, thus ice is less dense than water.
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    So if you were to explain why ice is less dense than water as simply as possible, what would be the good wording?

    'Ice is less dense than liquid water because hydrogen-bonds are longer'

    Doesn't sound like a solid explanation to me...
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    (Original post by sonic23)
    So if you were to explain why ice is less dense than water as simply as possible, what would be the good wording?

    'Ice is less dense than liquid water because hydrogen-bonds are longer'

    Doesn't sound like a solid explanation to me...
    In water the hydrogen bonds are made and broken. In Ice the hydrogen bonds are in fixed position and therefore there are gaps in the lattice. Therefore ice is less dense than water.
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    I thought it was because that.. the hydrogen bonds in ice hold it in an open lattice structure and therefore making it less dense than water
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    How bout this beastly answer:

    Water is considerably less dense than it's solid counterpart (ice) and this unusual property is considered to be due to the hydrogen bonding in water. In ice, the hydrogen bonds hold the water molecules apart in an open lattice structure. When the ice melts, the rigid hydrogen bonds break and the water molecules come closer together, making it more dense than ice.


    OH YEAH WHA U THINK OF MA ANSWER GUYS!!
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    (Original post by partysunil)
    How bout this beastly answer:

    Water is considerably less dense than it's solid counterpart (ice) and this unusual property is considered to be due to the hydrogen bonding in water. In ice, the hydrogen bonds hold the water molecules apart in an open lattice structure. When the ice melts, the rigid hydrogen bonds break and the water molecules come closer together, making it more dense than ice.


    OH YEAH WHA U THINK OF MA ANSWER GUYS!!
    I think you just said the same as the people before you in a longer, much less interesting way.
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    (Original post by SillyFencer)
    I think you just said the same as the people before you in a longer, much less interesting way.
    thats subjective to whether you find chemistry interesting
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    (Original post by partysunil)
    How bout this beastly answer:

    Water is considerably less dense than it's solid counterpart (ice) and this unusual property is considered to be due to the hydrogen bonding in water. In ice, the hydrogen bonds hold the water molecules apart in an open lattice structure. When the ice melts, the rigid hydrogen bonds break and the water molecules come closer together, making it more dense than ice.


    OH YEAH WHA U THINK OF MA ANSWER GUYS!!
    Answers too long. Mines to the point and will get all the marks. :yep:
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    I think it is because the most stable form of ice involves four hydrogen bonds for each water molecule, which invokes an arrangement of H2O molecules that create 'skeleton' structure. This structure has lots of space (i.e. will therefore be less dense).

    The structure of water is not known, but the interactions between the liquid water molecules will obviously not involve this arrangement, and therfore the molecules can be packed more closely [resulting in the ice being less dense].
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    (Original post by EierVonSatan)
    The actual structure of liquid water is unknown, but it is thought than the arrangement in ice is a result of the longer hydrogen bonds, thus ice is less dense than water.
    That's incredible. Why have I never heard this before?! Can you explain this a bit more to me? I'm just interested.
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    (Original post by marshey)
    That's incredible. Why have I never heard this before?! Can you explain this a bit more to me? I'm just interested.
    it's not on the syllabus, u just need to know open lattice, longer hydrogen bonds.
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    (Original post by partysunil)
    it's not on the syllabus, u just need to know open lattice, longer hydrogen bonds.
    Yeah, I had to know this for both Biology and Chemistry last year . But I'm just interested in the idea that we don't know the actual structure of water yet. It seems incredible to me...
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    (Original post by marshey)
    That's incredible. Why have I never heard this before?! Can you explain this a bit more to me? I'm just interested.
    Well all I can say is there is no universally accepted structure to liquid water :p: Ice is easier as the molecules don't move around much and you can get X-ray/neutron scattering data on it. There are about seven(?) different models for how water behaves in bulk. One model suggests that there are several different layers to it, each becoming more ordered (ice-like) the deeper you go into the bulk.
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    (Original post by DeanK2)
    I think it is because the most stable form of ice involves four hydrogen bonds for each water molecule, which invokes an arrangement of H2O molecules that create 'skeleton' structure. This structure has lots of space (i.e. will therefore be less dense).

    The structure of water is not known, but the interactions between the liquid water molecules will obviously not involve this arrangement, and therfore the molecules can be packed more closely [resulting in the ice being less dense].
    :yep: good answer

    taken from the revise AS chem revision book
    "For most substances, as the temperature drops below its freezing point the density increases as a solid forms. This is not the case for water. The density of ice changes at around 4*C. There are 4 groups around each oxygen atom, arranged tetrahedrally in three dimensions by hydrogen bonding. This leads to an 'open' structure with large spaces in it."

    Because of its open structure ice is less dense than water.
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    not sure why its less dense but when water turns to ice, I do not believe the bonds get longer they form a rigid structure creating a solid lattice, this will take the from or shape of its container, due to the unique properties of water, the hydrogen bonds are simply just made stronger due to a decrease in temperature (generally below zero degrees).
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    bit vague and wordy nil i got lost in your answer try bullet points and help the examiner
 
 
 
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