EQUILIBRIUM HELP: Freezing a carbonated drink. (1 Viewer)

[Eddyah]

I pose to you a question (from my teacher):

Why do bottles(or cans) of carbonated drinks explode when you ut them in the freezer?

My answer is pretty rough since my teacher still has my prac but off the top of my head:
1) The H2O molecules freeze and expand as it changes to a solid state. This causes increased pressure on the bottle causing it to explode.

2) Also, as water molecules are turning to solid state, they form a lattice due to hydrogen bonds (preliminary crap). Because the water molecules are being used up, the following equlibrium reaction shifts to the left:

CO2(g)+H2O(l) <> CO2(aq) + H2O(l) <> H2CO3(aq)..yada yada

So more CO2 is produced to balance the equilibrium.

I got part 2 wrong, although i think its correct seeing as CO2 has a freezing point of -78.5 degrees. I had in my mind that it would be 'forced' out of the water into a gaseous state. My teacher argued that i am contradicting Le chateliers principle as equlibrium would shift to the right to produce more heat to counter balance the temperature drop.

Opinions please.

Cheers, Eddy

 

[airie]

I agree with your teacher

The net equation of the equilibrium would be CO_2(g) <--> CO_2(aq) + energy.

I don't understand your argument that CO2 would be "forced out" of water into a gaseous state - on the contrary, seeing that temperature is dropped, the exothermic side of the equilibrium would be favoured and more CO2 would tend to dissolve in order to release heat as an attempt to counteract the change in temperature. So in the end you just have all these gas bubbles trapped in water ice, which takes up more space due to its lower density (compared to liquid water) and thus places more pressure on the container.

 

[Eddyah]

I agree with your teacher

The net equation of the equilibrium would be CO_2(g) <--> CO_2(aq) + energy.

I don't understand your argument that CO2 would be "forced out" of water into a gaseous state - on the contrary, seeing that temperature is dropped, the exothermic side of the equilibrium would be favoured and more CO2 would tend to dissolve in order to release heat as an attempt to counteract the change in temperature. So in the end you just have all these gas bubbles trapped in water ice, which takes up more space due to its lower density (compared to liquid water) and thus places more pressure on the container.

would these CO2 bubbles be chemically bonded with the water though?

 

[airie]

would these CO2 bubbles be chemically bonded with the water though?

If all water becomes solid ice, then no, it'll be just bubbles, as water molecules would form a lattice that excludes CO2.

Hmm, btw, I think I see what you mean by "forcing out" CO2 now I'd modify my answer as this: in the freezer, as the temperature drops, more CO2 would dissolve in water in order to produce more heat, to counteract the temperature change; then as surrounding water begins to freeze, since CO2 molecules only interact with water molecules by dispersion forces (and thus are excluded from the hydrogen-bonding-based ice lattice), air bubbles form. As ice takes up more space, in total inside the container, less space is left for the air bubbles, thus pressure on the walls of the container increases and it could explode.

That's the best explanation I give now

 

[Eddyah]

Hmm, btw, I think I see what you mean by "forcing out" CO2 now I'd modify my answer as this: in the freezer, as the temperature drops, more CO2 would dissolve in water in order to produce more heat, to counteract the temperature change; then as surrounding water begins to freeze, since CO2 molecules only interact with water molecules by dispersion forces (and thus are excluded from the hydrogen-bonding-based ice lattice), air bubbles form. As ice takes up more space, in total inside the container, less space is left for the air bubbles, thus pressure on the walls of the container increases and it could explode.

That's the best explanation I give now

Im cool with that

Cheers for your help