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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: firedamage on February 28, 2009, 04:20:39 AM

Title: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 04:20:39 AM

Why the initial  temperature of HCl is at 21'C?have anything influence the temperature?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Borek on February 28, 2009, 04:29:01 AM

Huh? I have HCl at initial temperature 18 deg C, so it is not 21.

Geez, man, we are not mind readers, you have to give us a chance of understanding what you are asking about.

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 04:49:32 AM

then why it is 18'C?y it doesnt follow the room temperature?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Borek on February 28, 2009, 04:56:34 AM

It is cold where I store my acid.

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Astrokel on February 28, 2009, 05:15:24 AM

:o lol

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 05:27:43 AM

y dont it follow the temperature of room??

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: sjb on February 28, 2009, 05:30:04 AM

Different rooms have different temperatures?

Seriously, what is the point of this question?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 09:16:56 AM

reaction between HCl and NaOH:
1)using a measuring cylinder,measure 45ml of 1 M HCL.pour into the reaction vessel and determine the temperature of the HCl.record this temperature on your report sheet.
2)measure 5ml of NaOH using another measuring cylinder.
3)Add NaOH to the HCl in the reaction vessel all at once and carefully stir the mixture withe the thermometer.record the highest temperature.

#Why the temperature in the reaction between HCl and NaOH decrease after it increase?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Astrokel on February 28, 2009, 09:23:21 AM

Quote

#Why the temperature in the reaction between HCl and NaOH decrease after it increase?

Why it increases? - What type of reaction is this?
Why it decreases after increases - Many already answered

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Arkcon on February 28, 2009, 09:26:15 AM

That happens, in this universe.  You get something hot, say a cup of coffee in the microwave, or your neutralization reaction.  After a while, the object loses it's heat, to the environment, and gets cold.  A giant pot of water stays hot long after you stop heating it.  A cup of coffee get cold sooner.  Your graduated cylinder even faster.  Heat is heat.  There is nothing special about the cooling properties of a solution of hydrogen chloride gas in water (HCl,)  or NaCl, as is the case when your reaction is complete.

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 07:59:58 PM

why the temperature remain unchanged after reach a  certain point?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: nj_bartel on February 28, 2009, 08:08:04 PM

Because it's reached the state of greatest disorder - an equilibrium with the outside environment.

P.S.  This was a great post  :P

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 09:11:02 PM

no..
i mean that:
why 30ml HCl+25ml NaOH,temperature changed=5'C
      25ml HCl+30ml NaOH,temperature changed=5'C
why the temperature changed is the same?the initial tempereature of HCl is 21'C     

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: enahs on February 28, 2009, 09:18:07 PM

heat of neutralization

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: firedamage on February 28, 2009, 09:25:13 PM

means tat the heat of neautralisation remain the same?

Title: Re: Why the initial temperature of HCl is at 21'C?
Post by: Arkcon on February 28, 2009, 09:28:45 PM

Quote from: firedamage on February 28, 2009, 09:11:02 PM

no..
i mean that:
why 30ml HCl+25ml NaOH,temperature changed=5'C
      25ml HCl+30ml NaOH,temperature changed=5'C
why the temperature changed is the same?the initial tempereature of HCl is 21'C     

Some answers to that question are given in your other post today, over here:

http://www.chemicalforums.com/index.php?topic=31624.msg120723#msg120723

You should try to avoid doing that, starting new threads for different parts of the same question, they're eventually going to connect, and we don't need the redundancy.