How long does it take to cool down a Ten-Pack?

[GasX]

Originally posted by: minendo

Originally posted by: werk

Originally posted by: notfred
Rock salt (or salt in general) doesn't make anything colder.

Read.

That discusses how salt lowers the freezing point, which is not the same as making the temperature drop.

Tap water is unable to drop below 32 degrees (else it becomes ice) By adding rock salt, you allow the freezing point to drop thereby allowing the water (now called brine) to drop to below 32 degrees. Since it is the water that cools the beer and not the ice, you are providing a greater temperature gradient and a faster way of cooling. Also, the final equilibrium temperature will be lower. Thus, rock salt will allow the beer to get colder than it could get without...

QED

 

[Jzero]

Dissolving NaCl is endothermic. You need energy to separate the ions in the salt. That energy comes from heat. When salt is dissolved in water, the overall temperature of the system decreases because the Na and Cl ions absorb some of the heat when their bonds break.

That's it. There's no further magic. Yes, the freezing point of the water will decrease. That's not the same as the temperature of the system decreasing.

 

[loup garou]

Originally posted by: Jzero
When salt is dissolved in water, the overall temperature of the system decreases

the freezing point of the water will decrease. That's not the same as the temperature of the system decreasing.

What are you trying to say?

 

[Dudd]

Originally posted by: Jzero
Dissolving NaCl is endothermic. You need energy to separate the ions in the salt. That energy comes from heat. When salt is dissolved in water, the overall temperature of the system decreases because the Na and Cl ions absorb some of the heat when their bonds break.

That's it. There's no further magic. Yes, the freezing point of the water will decrease. That's not the same as the temperature of the system decreasing.

But the main reason you put rock salt onto snowy roads and into ice solutions is to lower the freezing point. I'm not denying that NaCl dissolving is endothermic. However, taking heat away from 32 degree water will only make more of the water freeze. The temperature of the solution will not change. If the endothermic reaction was the only effect of salt, then it would have the opposite effect on roads than is intended. Rather than melt, the snow would become colder, not turn into water as intended. You'll notice that ice on roads stops when the temperature falls too far. That's because at that point, all the salt in the world will not lower the freezing point to the depths needed to melt the snow. Instead, sand is thrown down solely for traction.

/feels very geeky right now, but could be working

 

[TheNinja]

Originally posted by: Mwilding

Originally posted by: minendo

Originally posted by: werk

Originally posted by: notfred
Rock salt (or salt in general) doesn't make anything colder.

Read.

That discusses how salt lowers the freezing point, which is not the same as making the temperature drop.

Tap water is unable to drop below 32 degrees (else it becomes ice) By adding rock salt, you allow the freezing point to drop thereby allowing the water (now called brine) to drop to below 32 degrees. Since it is the water that cools the beer and not the ice, you are providing a greater temperature gradient and a faster way of cooling. Also, the final equilibrium temperature will be lower. Thus, rock salt will allow the beer to get colder than it could get without...

QED

You could have just copied my post a little ways up and said "ya, what he said" b/c I just said the exact same thing plus I gave good reasoning

 

[Jzero]

Originally posted by: werk

Originally posted by: Jzero
When salt is dissolved in water, the overall temperature of the system decreases

the freezing point of the water will decrease. That's not the same as the temperature of the system decreasing.

What are you trying to say?

If you disolve salt in water, the FREEZING POINT of the water will decrease. If you heat the saltwater solution to 80 degrees, the freezing point will not change as long as the salt concentration remains constant.

OTOH, at the time you dissolve the salt in the water, the water itself gets COLDER.

There are two numbers - the freezing point, which is a constant, and the temperature of the water which is related to the amount of energy in the water.

The colder the surrounding environment, regardless of whether it's solid, liquid or gas, the faster the beer gets cold. You could use solid dry ice, you could use liquid nitrogen. But you're more likely to have ice and salt laying around your house.

 

[Jzero]

But the main reason you put rock salt onto snowy roads and into ice solutions is to lower the freezing point. I'm not denying that NaCl dissolving is endothermic. However, taking heat away from 32 degree water will only make more of the water freeze. The temperature of the solution will not change. If the endothermic reaction was the only effect of salt, then it would have the opposite effect on roads than is intended. Rather than melt, the snow would become colder, not turn into water as intended. You'll notice that ice on roads stops when the temperature falls too far. That's because at that point, all the salt in the world will not lower the freezing point to the depths needed to melt the snow. Instead, sand is thrown down solely for traction.

Both things happen.
We put the salt on the roads b/c it lowers the freezing point and causes the water to melt.
It's good for cooling your beer because it makes it colder.

 

[loup garou]

Originally posted by: Jzero

Originally posted by: werk

Originally posted by: Jzero
When salt is dissolved in water, the overall temperature of the system decreases

the freezing point of the water will decrease. That's not the same as the temperature of the system decreasing.

What are you trying to say?

If you disolve salt in water, the FREEZING POINT of the water will decrease. If you heat the saltwater solution to 80 degrees, the freezing point will not change as long as the salt concentration remains constant.

OTOH, at the time you dissolve the salt in the water, the water itself gets COLDER.

There are two numbers - the freezing point, which is a constant, and the temperature of the water which is related to the amount of energy in the water.

The colder the surrounding environment, regardless of whether it's solid, liquid or gas, the faster the beer gets cold. You could use solid dry ice, you could use liquid nitrogen. But you're more likely to have ice and salt laying around your house.

I see, I misread your earlier post, thinking you first said that the system temperture decreased, then contradicted yourself. I think we're on the same page now.

And to anyone who doubts that this works, just try it...it works great!

 

[TNTrulez]

Adding a salt to water will make the temperature of the water drop. It also lowers the freezing point and raise the boiling point.

Those that think otherwise needs to brush up on chemistry and physics.

 

[kermalou]

when can you find a 10 pack?

i thought they were always in multiples of 6 for some reason (except for Guiness 4 packs)

 

[loup garou]

Originally posted by: kermalou
when can you find a 10 pack?

i thought they were always in multiples of 6 for some reason (except for Guiness 4 packs)

Way to read.

 

[RayH]

Salt alone only lowers the freezing point. It's the phase change from ice to water which causes the temperature to drop.


Water Phase Energy

 

[Jzero]

Originally posted by: RayH
Salt alone only lowers the freezing point. It's the phase change from ice to water which causes the temperature to drop.


Water Phase Energy

There's more to it than that. The phase change does not occur spontaneously.
Look for Heat Of Solvation towards the bottom.

 

[WinkOsmosis]

Originally posted by: werk

Originally posted by: minendo

Originally posted by: werk
Where do you think the heat necessary to melt the ice comes from?

What heat? Now you are discussing heat, when we want to make the beer cold. By adding salt to ice all you do is turn it into ice-water.

Haven't you ever made ice cream before? The salt causes the freezing point of the ice to lower, so it melts. In order for it to melt, it needs to draw heat from its environment. The cans of beer are in its environment so heat is drawn out from the beer, making it cold.

Yeah. Freezing point is also known as melting point. This means that it will melt at a lower temperature. That temperature is what the ice will cool the beer to. Just like if the temperature is not lowered, the beer would be cooled to 0°C.

 

[TechnoKid]

Drink the beer first then try and figure it out. Should be entertaining.

Oh, and two seconds is the quickest....liquid nitrogen....