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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: stevie10 on August 08, 2015, 01:52:03 AM

Title: What is temperature of water when..
Post by: stevie10 on August 08, 2015, 01:52:03 AM
Hello Folks,

I was wondering if someone could help me.  We have a wet ice maker in the lab and when it breaks we put the ice from the machine into a -40 C freezer to preserve it.  What temperature will the ice be when it is removed from the -40 C freezer?

Possibly a silly question? but hey ho. 

p.s. the ice is made from tap water (not DI)

Many thanks

Stevie
Title: Re: What is temperature of water when..
Post by: Dan on August 08, 2015, 05:22:59 AM
What temperature so you think it will be? Why?
Title: Re: What is temperature of water when..
Post by: stevie10 on August 08, 2015, 06:12:14 AM
Well water boils at 100 C and evaporates before it can get any warmer (with the exception of altitude/pressure).  Therefore it cannot get any warmer.

As ice forms at 0 C, does it conduct cold (get colder at -40 C?)?  Say like a piece in of metal would.  Would also be a difference with deionised water?

As risk of sounding like a complete goon I think it would be -40 C.

Thanks
Title: Re: What is temperature of water when..
Post by: Borek on August 08, 2015, 06:34:33 AM
Quote from: stevie10 on August 08, 2015, 06:12:14 AM
Well water boils at 100 C and evaporates before it can get any warmer (with the exception of altitude/pressure).  Therefore it cannot get any warmer.

Sure it can, you can heat the steam up. Note that when you say "water" you mean "liquid", when we say "water", we mean substance with a formula H2O, whatever its state of matter is.

Quote
As risk of sounding like a complete goon I think it would be -40 C.

That's the only thing you got 100% right ;)

Yes, water freezes at 0°C, but nothing stops it from getting colder.
Title: Re: What is temperature of water when..
Post by: Arkcon on August 08, 2015, 06:53:42 AM
Do review the cooling curve:  https://en.wikipedia.org/wiki/Cooling_curve  There are many such images in all basic chemistry textbooks.  A mixture of ice and water, in a container is by definition 0° C.  Or a pan of water, boiling, is defined to be at 100 °C.  (Of course, there are real world deviations, however slight.)

Quote
Say like a piece in of metal would.  Would also be a difference with deionised water?

You mean a solid block of ice?  Why would it be different than metal?  Or wood?  Or stone?  Do they feel different to you when you touch them on a cold day?  Warning: That is a trick question.
Title: Re: What is temperature of water when..
Post by: stevie10 on August 08, 2015, 07:16:15 AM
Thanks for the speedy replies.

Sorry for the typos just off nightshift.

I understand that it will just conduct the cold the same way most other things will.

I will check out the aforementioned links for more info.

Cheers 😀
Title: Re: What is temperature of water when..
Post by: stevie10 on August 08, 2015, 12:00:31 PM
P.s.  I seen the smarter every day vid with the explanation of differences in touch temperature.

Nice try though 😉