freezing water

[Dencology]

freezing water is endothermic or exothermic?
my guess is endothermic because water is gaining surrounding heat. but i have the answer as exothermic, since heat must be removed from water to make it freeze

what do you have to say?

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[ucla2134]

freezing water is endothermic or exothermic?
my guess is endothermic because water is gaining surrounding heat. but i have the answer as exothermic, since heat must be removed from water to make it freeze

what do you have to say?

it is exothermic. Just think about it, you go from solid--> liquid--> gas. At each stage, you need to put energy in to separate the molecules. Thus, it is endothermic. Now, if you go reverse, then it is exothermic. I think learn this one from destroyer or kaplan.

 

[Dencology]

great. i like this explanation. thanks. Now i have another question:

which of the following conditions are required in order for a negative delta G to indicate a spontaneous reaction?

a. constant pressure
b. constant temp
c. constant vol

1. a
2. b
3. a,b
4. a,b,c

 

[pidbull]

great. i like this explanation. thanks. Now i have another question:

which of the following conditions are required in order for a negative delta G to indicate a spontaneous reaction?

a. constant pressure
b. constant temp
c. constant vol

1. a
2. b
3. a,b
4. a,b,c

I would say A, but I have no clue why, I think I might have just read something along those lines, what is the correct answer and why?

 

[utdent20]

hey Dencology, i want to know the answer to this delta G question?? can you please post the answer or have any reasoning post that too, coz this question is killing me..

 

[GCT]

freezing water is endothermic or exothermic?
my guess is endothermic because water is gaining surrounding heat. but i have the answer as exothermic, since heat must be removed from water to make it freeze

what do you have to say?

Unfreezing water would be the endothermic process, take a block of ice and it is going to cool your room simply because it's taking up the surrounding heat.