Where does heat go when something turns from liquid to solid

[fastfingers]

When water turns from liquid to solid, it is an exothermic reaction. Where does the heat get release to? From what I remember, a good way to tell if a reaction is exothermic is if it feels warm around it and it's endothermic if it feels cold. How come when water turns from liquid to solid, nothing ever feels warm around it? Could somebody explain to me where the heat releases to?


EDIT: sorry wrong place to post this. I've repost appropriately.

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[apumic]

When water turns from liquid to solid, it is an exothermic reaction. Where does the heat get release to? From what I remember, a good way to tell if a reaction is exothermic is if it feels warm around it and it's endothermic if it feels cold. How come when water turns from liquid to solid, nothing ever feels warm around it? Could somebody explain to me where the heat releases to?

The surroundings. If we are cooling water in a freezer, for instance, at 1 atm pressure, the heat energy is released into the freezer (which causes the temperature to decrease over time and the water to freeze). It is not a chemical reaction but a physical state change. Think about what is going on intermolecularly and intramolecularly as we enter this state change. Ask yourself why this state change is occurring. I think the answers to your questions should become readily apparent through some thinking about it conceptually.

 

[fastfingers]

When water turns from liquid to solid, it is an exothermic reaction. Where does the heat get release to? From what I remember, a good way to tell if a reaction is exothermic is if it feels warm around it and it's endothermic if it feels cold. How come when water turns from liquid to solid, nothing ever feels warm around it? Could somebody explain to me where the heat releases to?

 

[PiBond]

it gets released to the surrounding environment. just because we can't feel it doesn't mean there isn't heat being released

 

[TwoPaddles]

Yeah just like in friction, where the energy gets converted to heat.

 

[fastfingers]

yeah, but I've been trying to think of an example where we can actually feel heat released. I can understand friction easier since the ground gets hot when there's friction, but how about liquid to solid?

 

[V5RED]

It isn't like a chemical reaction where you can touch a beaker and feel it happening. It isn't even really a chemical reaction, it is a phase change. I suppose if your body temperature was below 0 you could feel it, but otherwise you won't feel any heat coming from it directly.

Two ways to indirectly feel the heat are to either work in an ice cream shop where it gets super hot due to the exhaust from the freezing units or if you have a mini fridge like my old one, you could feel some of the heat being released through the grate on the back.

 

[SteveJMarist]

I think you're also confusing heat with temperature. It would explain why you're not "feeling" warmth when, say, an ice cube forms. Check out this website:

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/differ.html

It's short and simple and hopefully will help you.

 

[shopsteward]

Here's another website on the subject- heat is work and work is heat, right?

http://www.youtube.com/watch?v=KTHiIwxcexI

 

[SteveJMarist]

Here's another website on the subject- heat is work and work is heat, right?

http://www.youtube.com/watch?v=KTHiIwxcexI

I don't believe they are one in the same, but they are very much related. Heat typically refers to the transfer of energy, while work generally pertains to kinetic/mechanical energy. Don't quote me on this, but I suppose it is possible for the transfer of heat to be used as work. Also, doing work on an object (again I'm postulating here) can definitely transfer energy to the surroundings in the form of heat (like moving a box along a surface with friction).

That's my take on it anyway. I was not a physics major, so if I'm wrong, someone please correct me. I believe this debate is beyond the scope of the MCAT though, so for our purposes, I would keep the two concepts separate. Use heat for phase changes and work for a force applied over a certain distance (W = Fd).

 

[FUNinDC]

When water turns from liquid to solid, it is an exothermic reaction. Where does the heat get release to? From what I remember, a good way to tell if a reaction is exothermic is if it feels warm around it and it's endothermic if it feels cold. How come when water turns from liquid to solid, nothing ever feels warm around it? Could somebody explain to me where the heat releases to?


EDIT: sorry wrong place to post this. I've repost appropriately.

I was confused too but... I just read this:
"When a substance absorbs or releases heat, one of two things can happen: either its temp changes or it will undergo a phase change, but not both at the same time." Princeton Review G.Chem Review book, 2010, pg 95

That is why you can't "feel' the heat (deltaH) absorbed/released during a phase change but you can during a temp change.

 

[V5RED]

I was confused too but... I just read this:
"When a substance absorbs or releases heat, one of two things can happen: either its temp changes or it will undergo a phase change, but not both at the same time." Princeton Review G.Chem Review book, 2010, pg 95

That is why you can't "feel' the heat (deltaH) absorbed/released during a phase change but you can during a temp change.

The water won't change temperature, but whatever is receiving the heat will change temperature unless it too is going through a phase change.

If we were talking about melting ice, then if you place your hand on 0C ice, then although it would not be changing temperature until it had melted, you would feel cold due to the heat transfer.

 

[Pisiform]

Liquid to Solid ==== Exothermic RXN ==== Heat lost is used up in making bonds

 

[Rabolisk]

Making what bonds?

 

[V5RED]

Making what bonds?

Making no bonds. The post below mine about ice formation causing bonds is completely incorrect.

 

[Rabolisk]

I know, I was trying to give him a chance to correct himself.

 

[V5RED]

I know, I was trying to give him a chance to correct himself.

I apologize both for misinterpreting your post as well as if I came across as patronizing since that was not my intent.

 

[orthomyxo]

You aren't making any bonds when liquid water turns to ice, at least none that involve electron transfer. You simply have water molecules aligning such that their dipoles can interact. No chemical reaction is happening.

 

[Pisiform]

You aren't making any bonds when liquid water turns to ice, at least none that involve electron transfer. You simply have water molecules aligning such that their dipoles can interact. No chemical reaction is happening.

Ohh Yes ... thanks for correcting me. I dont even know why I made that stupid comment. What the hell was I thinking 😕